Categorized Glossary of Automotive Terms

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Please note that the definitions included in this Glossary reflect the manner in which these terms are used on the Edmunds.com website, which in some instances may differ from their meaning in other contexts.

Cabin | Electronics | Features and Options | Fuel/Economy/Impact | General | Insurance | Maintenance | Performance | Pricing and Incentives & Rebates | Safety & Crash Test | Specifications | Vehicle Classification | Warranty

Cabin

Air conditioning
The cooling and dehumidification of a vehicle's cabin air.
Air filtration
The removal of solid particulates (such as dust, pollen, mold and bacteria) from a vehicle's cabin air by a filter placed in the ventilation system.
Auxiliary lighting
A halogen lamp or light-emitting diode (LED) that is used to illuminate a specific region or part of a vehicle (such as the glove box or footwell) and is not located in the vehicle's headliner.
Bolstering
Upholstered foam supports integrated into a seat that help keep the driver or passenger in an optimal position.
Cabin lighting
Halogen lamps and/or light-emitting diodes (LEDs) located in a vehicle's headliner that illuminate a vehicle's interior space in its entirety.
Center console trim
Wood, composite, leather or metal adornments intended to supplement the aesthetic elements of a vehicle's center console.
Climate control
The computer-controlled regulation of heating and air conditioning systems to accommodate a user-specified temperature setting.
Climate-controlled seats
Seats that have internal heating and cooling mechanisms.
Compass
A digital or analog display that indicates the direction a vehicle is facing.
Console
A storage area located in a vehicle's dash or headliner, between seats or underneath the seats.
Cooled seats
Seats that can direct air from the air conditioning system through tiny holes in the center section of the seat bottom.
Engine hour meter
A device that records the number of hours an engine has run over its lifetime.
Exterior mirrors adjustment type
The type of position adjustment control for the exterior mirrors: power, memory or manual.
External temperature display
The digital display of the ambient air temperature around a vehicle.
Front seat type
The type of front seating: bucket seats, sport seats, split-bench seats or captain's chairs.
Gauges
See "instrumentation."
Heads-up display
A digital display projected from a vehicle's dashboard onto its windshield to provide information within the driver's direct line of sight.
Heater
A heat exchanger placed in the ventilation system that diffuses heat from the engine's cooling system into an airstream generated by an inline fan.
HVAC
Heating, ventilation and air conditioning.
Instrumentation
Digital and/or analog displays used to convey to the driver information such as dynamic engine parameters, operating conditions, RPM, speed and water temperature.
Interior lighting
Halogen lamps or light-emitting diodes (LEDs) used to illuminate a vehicle's interior space.
Interior trim
Wood, composite, leather or metal adornments intended to supplement the aesthetic elements of a vehicle's interior.
Liftgate window
The window integrated into the hinged lid of a hatchback, wagon, SUV or crossover that swings upward to provide access to the cargo area.
Low fuel warning indicator
An alert, usually in the form of a halogen lamp or LED, warning the driver of a low fuel supply.
Lumbar support
A mechanical or pneumatic device that matches a vehicle's seat back to the contours of the driver or passenger.
Massaging seats
Seats that contain moving mechanical elements in the seatback, usually with several selectable settings.
Pedal adjustment
The mechanism that controls the position of a vehicle's gas, brake and/or clutch pedal to suit the needs of the driver.
Rear area cargo cover
A feature that uses rainfall sensors to engage the wipers and adjust wiper speed accordingly.
Rear defroster
A device that melts ice or frost or removes condensation from a vehicle's rear window.
Rear HVAC
The climate-control system used to regulate heating and air conditioning for the area of a vehicle behind the front row seating.
Rear seat type
The type of rear seating: bench seats, bucket seats, removable seats, split-bench seats, captain's chairs or seats that convert into a bed.
Row count
The number of available rows of seating in a vehicle.
Seat adjustment type
The type of adjustment control for the seats: manual, power or power-with-memory.
Seat extension
An attached support, consisting of a metal frame with upholstered foam, that lengthens a vehicle's seat bottom.
Seat features
Devices integrated into a vehicle's seats that control seat temperature, seat adjustability, driver comfort and other settings.
Seatback storage
A storage pocket that is either attached to the backside of the seat or integrated into the seat itself.
Seating capacity
The number of people that can be safely seated and restrained in a vehicle, including the driver.
Side pockets
A storage pocket that is either attached to the door panel of a vehicle or integrated into the vehicle door.
Steering wheel adjustment
The mechanism that controls the position of a vehicle's steering column to suit the needs of the driver.
Steering wheel controls
Electronic controls for a vehicle's entertainment, cruise control, telematics and/or climate control systems that are mounted on the steering wheel for the driver's convenience.
Sun Sensor
A dash top sensor, usually dome-shaped, that measures the "sun load" on the vehicle to help improve the accuracy of the automatic climate control system.
Tachometer
An instrument that tells the driver how fast the engine is rotating, commonly including a redline to indicate the maximum engine speed.
Trip computer
An electronic device used to calculate and display trip information, such as distance traveled, average speed and fuel economy.
Under seat storage
A storage console located under a vehicle's seat.
Upholstery
Cloth, leather or synthetic material used to cover a vehicle's seats, door panels, arm rests and headrests.
Vanity mirrors
Mirrors commonly placed on the underside of a vehicle's sun visors intended to be used for personal grooming.
Ventilated seats
Seats that can direct ambient cabin air through tiny holes in the center section of the seat bottom.
Window control
The manner in which a vehicle's windows are operated: manual control, power control, one-touch, automatic or remote control.
 

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Electronics

Antenna type
The type of antennas used in vehicle audio systems and navigation systems: mast, power telescoping, element and diversity.
Audio format
The format of digital compression readable by a vehicle's audio system, such as WMA, MP3, WAV, SACD or AAC.
Audio remote control
A wireless device that uses infrared or radio waves to control a vehicle's sound system.
Auxiliary input (Audio)
A method of connecting a peripheral media player to a vehicle's entertainment system, either wired (for example, through an RCA jack, a USB port or a 1/8" TRS plug), or wirelessly (for example, through Bluetooth, A2DP or infrared).
Disc changer
An in-dash or remote-mounted CD or DVD/CD player that can store and read multiple discs and play them through the vehicle's audio system.
Gyro sensor
A device that enables a vehicle's navigation system to determine the direction the vehicle is facing.
Headsets
A pair of small speakers that, when placed close to a passenger's ears, enables the passenger to listen to a vehicle's sound system without disturbing other passengers.
Head unit
The central control unit for a vehicle's entertainment system.
In-car cellular phone
A cellular phone that either (i) has a handset built into the vehicle, or (ii) is a portable unit with an accompanying dock built into the vehicle that enables operation through the vehicle's entertainment and stereo system.
Individual monitors
More than one video monitor in the rear passenger area of a vehicle with a rear seat entertainment system.
Map storage
The media on which the maps for a vehicle's navigation system are stored (generally CD, DVD or hard drive).
Navigation interface
The means by which a vehicle's navigation system is controlled, including touch screen, jog dial, push button and/or voice activation.
Navigation system
A device that communicates with global positioning satellites to determine a vehicle's physical location and plot a course using stored map information.
Premium audio
A sound system that has been provided to the vehicle manufacturer by a name brand audio manufacturer.
115V AC Outlet
An electrical socket receiving 115v AC current produced by a vehicle's charging system.
Radio data system
A small portion of the FM frequency that is allocated for broadcasting alphanumeric news, traffic and song information.
Real time traffic updates
Traffic congestion information gathered by road sensors and other means read by a vehicle's navigation system through communications satellites.
Rear seat entertainment system
The elements of a vehicle's entertainment system accessible to rear seat passengers.
Satellite communication
A proprietary system used to send and receive vehicle data, crash information, concierge services and navigation to and from a vehicle through communications satellites.
Satellite radio
A radio receiver that receives radio signals broadcast from communications satellites rather than a conventional terrestrial tower.
Separate rear audio
The capability of a vehicle's sound system to deliver a different audio source to the rear seat passengers than the audio source being delivered to the front seat passengers.
Speaker configuration
The number and arrangement of speakers as well as the number of independent speaker channels (including center and subwoofer channels) that are supported by a vehicle's sound system.
Speed-sensitive volume control
A feature in some vehicle sound systems that lowers the speaker volume in proportion to vehicle speed.
Storage media
The physical media that a vehicle sound system is capable of playing and/or recording to, such as CD, DVD, hard drive, USB or flash drive.
Telematics
The integrated use of telecommunications in a vehicle.
12V DC outlet
An electrical socket receiving 12v DC current produced and stored by a vehicle's charging system.
Universal remote control
A wireless device that can be programmed to control all aspects of a vehicle's entertainment system.
Video game input
A set of RCA plugs located in the rear passenger section of a vehicle.
Video monitor
A color or monochromatic liquid crystal display used for information, navigation or video located in a vehicle's dashboard, headliner or headrests.
Video remote control
A wireless device that uses infrared or radio frequency to control a vehicle's video system.
Video source
A device that produces a video signal to be displayed by a vehicle's entertainment system.
Watts
A measure of the amount of power that an amplifier is capable of producing or a speaker is capable of enduring.
Wireless data link
A method of transferring digital data wirelessly through Bluetooth or WiFi technology.
 

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Features and Options

Adjustable pedals
Accelerator and break pedals that can be moved closer to or further away from the driver's seat.
Auxiliary features
Factory-installed, optional parts that supplement similar existing systems, such as a transmission cooler, engine cooler or a secondary gas tank, that are typically available on trucks and SUVs.
Bed extender
A device that may be added to a pickup truck's bed when the tailgate is open, that sits on top of the tailgate, and that forms an enclosure that permits items that extend past the bed and onto the tailgate to be carried without risk of falling out.
Bed features
Factory-installed, optional accessories that add functionality or longevity to a truck's bed, such as a bed extender, tonneau cover or bed liner, that are typically available on trucks and SUVs.
Bed liner
A heavy-duty plastic liner or spray-on coating that protects the inner painted surface of a pickup truck's cargo box.
Bed type
Type of truck bed: long, short, flare-side, step-side, dually and flat beds for trucks, and dump beds and tanks for SUVs.
Beverage cooler
A refrigerated storage area intended to cool beverages using a vehicle's air conditioning system or a separate phase-cooling system.
Block heater
An electric heater installed into a freeze plug hole in an engine block that preheats engine coolant in order to help start a vehicle under extremely cold weather conditions.
Bumpers
A supplemental device designed to protect a vehicle's frame and/or body from collision damage.
Carburetor
A device used on older internal combustion gasoline engines that is mounted on the engine's intake manifold and supplies fuel to the engine.
Cargo area features
Built-in amenities that serve a specific purpose in the cargo areas of a vehicle.
Cargo tie downs
Hooks, straps or eyelets that function as anchors for cargo nets and ropes used to secure objects.
Convertible roof type
The type of convertible roof tops, including soft tops, hard tops, T-tops, Targa-style tops, and tops that are manual or power operated.
Convertible wind blocker
Also known as an "aeroboard." An on a convertible vehicle, the glass or plastic shield that prevents reversion of high-velocity air as it passes over the low-pressure, low-velocity air in the passenger compartment.
Cruise control
A device that, when engaged by the driver, automatically controls a vehicle's speed.
Cylinder deactivation
A feature of some engines that allows the engine to turn off two or more cylinders in order to maximize fuel efficiency.
Diesel engine hour meter
A digital or analog display that shows the amount of time (in total hours) that a diesel vehicle's engine has run over its lifetime.
Direct injection system
A fuel injection system in which the injection nozzles are located inside the combustion chamber of each piston.
Easy entry
A device that automatically retracts a vehicle's power seats and/or steering column when the engine is switched off.
Electric battery type
The type of battery used to power the electric motor in a hybrid or electric vehicle:  lead-acid, flooded, gel, lithium ion, absorbed glass mat, Zebra Na/NiCL2 or NiZn traction.
Electric motor type
The type of electric motor in a hybrid or electric vehicle used to power the drive wheels: permanent magnet motor or other traction motor.
Fuel injection system
A device that atomizes fuel by forcibly pumping it through a small nozzle under high pressure and delivers it to the vehicle's engine.
Heated windshield
A windshield with tiny embedded heating elements that act to resist fogging.
Heated windshield wiper rests
Heating elements below the wipers that melt ice and snow when they freeze to the glass.
Intermittent wipers
A wiper setting that causes the wipers to pause for a driver-selected period between wipes.
Keyless ignition
A system that allows the activation by the driver of a push-button to start a vehicle if proximity sensors detect the electronic key inside the vehicle.
Light bar
Additional lighting mounted on a metal or plastic frame that is attached to a vehicle's roof, and that is typically available on trucks and SUVs.
Lip spoiler
A spoiler that is flush-mounted to a vehicle's trunk lid or liftgate that allows air to flow over it but not under it (and that is usually installed for aesthetic purposes).
Memory settings
Preset positions and settings (for power seats, mirrors or steering column positions for a vehicle's driver) or for the HVAC system, audio system, exterior mirrors or navigation system, that can be recalled using a button.
One-touch windows
Vehicle windows with a changeover switch that is capable of automatically rolling the window glass completely up or down (as well as functioning as a conventional momentary power window switch).
Optional equipment
Equipment that is not included in the manufacturer's base configuration of a vehicle.
Passenger memory settings
Preset power seat positions for the passenger that can be recalled using a button.
Plus size wheels
Also known as "up-sized wheels." Wheel and tire packages that are larger in diameter than those included in a vehicle's standard equipment.
Power activated release
The electronically controlled release of a vehicle's hatch or trunk (in contrast to a conventional cable-activated release mechanism).
Power steering
An electric and/or hydraulic system that multiplies, for ease and comfort, the force a driver exerts on the steering wheel.
Privacy glass
A vehicle window with a factory-installed tint, utilizing either a mylar covering or smoked glass, that has enough opacity to obscure the vehicle's interior from view.
Rain-sensing wipers
A feature that uses rainfall sensors to engage the wipers and adjust wiper speed accordingly.
Rear spoiler
An aerodynamic device attached to a vehicle's trunk lid or liftgate consisting of one or more airfoils supported by uprights that allows air to flow over it as well as under it, resulting in decreased lift and increased stability at high speeds.
Remote start
A feature of a vehicles' electronic key fob that controls the vehicle's ignition.
Remote trunk release
The control of a vehicle's power-activated release using a button on an electronic key fob or smart key.
Remote window operation
The control of a vehicle's power window system by one or more buttons on an electronic key fob or smart key.
Retained accessory power
A feature that permits the operation of a vehicle's power accessories after the key is removed from the ignition for a set period of time or until a door is opened.
Roof rack
A metal or plastic device attached to a vehicle that is used to anchor cargo to the vehicle's roof.
Roof spoiler
A spoiler that is mounted from the rearward-facing edge of a vehicle's roof to the liftgate just above the rear windshield, or to the upper edge of the rear windshield itself (and that is usually installed for aesthetic purposes).
Running boards
Rocker panel extensions that function as steps to aid the driver and passengers in the entering and exiting of tall vehicles.
Sliding rear window
A small window inside a truck's rear windshield that opens and closes by sliding on a system of metal or plastic rails attached to the windshield.
Smoked glass
A vehicle window that has been infused with pigment during manufacturing in order to provide enough opacity to obscure the vehicle's interior from view.
Snowplow prep
The hardware needed to attach a factory-optional, removable snowplow to a vehicle's front bumper and/or frame.
Soft-close doors
Doors that will pull themselves shut if they are not fully latched by the occupants.
Speed-sensitive wipers
A feature that increases the speed of the wipers with vehicle speed.
Spoiler
An attachment to a vehicle (or component of its body) originally introduced for the purpose of directing airflow over such device (or the entire vehicle) to decrease lift and increase stability at high speeds, but that is sometimes used on consumer vehicles solely for aesthetic reasons.
Sunroof
A fixed or operable opening in the roof of a vehicle that is covered with a metal or glass plug.
Sunshade
A removable or retractable device that limits or prevents light from passing through a vehicle's window.
Tint
A transparent plastic film applied to a vehicle's windows that reduces visible light transmission and, in some cases, rejects heat by reducing UV and infrared transmissions.
Tow hooks
Metal hooks or eyelets, either fixed or removable, that are attached to a structurally sound section of a vehicle's frame and used as pickup points for tow cables.
Trailer hitch
A metal device attached to a structurally sound section of a vehicle's frame that is used to support a trailer while coupling it to the vehicle.
Trailer wiring
A flat, four-way, weatherproof connector located near a vehicle's trailer hitch used to complete the circuits for a trailer's ground, running, left signal, right signal and break lights.
Two-stage unlocking
A remote electronic door lock system that opens the drivers door on the first press and the other doors on the second press.
Universal remote transmitter
An electronic device integrated into a key or key fob that controls a vehicle's remote-operated accessories.
Up-sized wheels
See "Plus size wheels."
Variable valve timing
An engine feature that allows the lift, timing or duration of the engine's valvetrain to be changed dynamically while it is in operation.
Wheel covers
A decorative metal or plastic disc that obscures a vehicle's stamped steel wheels, lug nuts and/or hubs from view.
Wheel locks
Special lugnuts intended to prevent wheel theft that can only be installed or removed with a specific wrench or key.
 

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General

Aftermarket accessory
An accessory or piece of equipment that is not included in the vehicle as manufactured, but is purchased and installed at the dealership or other automotive establishments.
Branded title
A permanent designation on a vehicle's title, registration or permit documents that indicates that a vehicle has incurred damage the repair of which is not possible or would cost more than the vehicle is worth, or that the vehicle has been sold for scrap. While branding designations vary by state, typical branding titles include rebuilt, salvage, irreparable and theft recovery.
Certified pre-owned vehicle
A used vehicle offered for sale by a franchised dealer for that vehicle make and who follows the manufacturer's requirements for "certifying" the vehicle (including inspection and service) and which, upon sale, is accompanied by a manufacturer-backed warranty.
CPO
See "Certified pre-owned vehicle."
Demo
(i) a test drive; (ii) a vehicle that has been used as a demonstration model by a dealership.
Lemon
A vehicle that is found to have numerous or severe defects not readily apparent before its purchase. Used both informally to mean a vehicle that proves to be defective, imperfect or unsatisfactory, and with more precise meaning in various states' "lemon laws" that provide vehicle purchasers certain rights.
OEM
Original equipment manufacturer, i.e., the manufacturer of a vehicle.
Program car
A "program car" is one that was owned by the manufacturer and given to employees for a short time to use for company business and later purchased at auction by the dealership. Sometimes former rental cars turn up on used car lots advertised as "program cars"; this will be revealed if you run a vehicle identification number (VIN) check using a service such as CARFAX or AutoCheck.
Salvage title
An automobile title with a notation that the vehicle has been damaged in excess of approximately 70% of its pre-accident market value. The exact percentage depends on the insurance provider and any applicable laws and regulations. This notation gets applied to a title when an insurance company pays a total-loss claim on a vehicle, but then sells the vehicle at an auction center.
Vehicle Identification Number
A Vehicle Identification Number, or "VIN," is the unique code that is assigned to an individual vehicle by its manufacturer and that distinguishes it from all other vehicles. No two vehicles can have the same VIN. Typically, the VIN is stamped into a plate or printed on a sticker and affixed to the vehicle in several different places, including inside the engine bay and on the driver's side door jamb.

Certain digits in the VIN identify a vehicle's attributes, including its final point of assembly, its model year, the manufacturer and, usually, the model of the vehicle. For a complete description of how to read a vehicle's VIN, please see Making Sense of Your VIN.

Modern, 17-digit VINs can be used to access many records relating to a vehicle, including ownership, accident and repair histories. Edmunds does not offer such reports, but our advertiser AutoCheck does. For more information, please see Which Vehicle History Report Is Right for You?.

Our VIN Check page is a central location for information about Vehicle Identification Numbers.
 

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Insurance

Actual cash value
Also referred to as "ACV." A method of valuing insured property that is computed by subtracting depreciation (based on the property's age and condition) from its replacement cost. Compare "Replacement cost."
ACV
See "Actual cash value."
Declaration page
Also referred to as the "Declaration of insurance." The portion of a property or liability insurance policy that states the name and address of policyholder, the property insured, its location and description, the policy period, the premiums and supplemental information.
Comprehensive insurance
Vehicle insurance that cover damage other than that caused by a collision with another vehicle or object.
Collision insurance
Vehicle insurance that cover damage caused by a collision with another vehicle or object.
Gap insurance
In a vehicle lease, insurance that covers any "gap" between (i) the amount the lessee's insurance company will pay to the lessee if the leased vehicle is stolen or destroyed, and (ii) the aggregate remaining amount the lessee owes at that time to the leasing company.
Replacement cost
A method of valuing insured property that uses the cost of replacing the property at current prices and does not take into consideration the property's condition or whether it has depreciated since first acquired. Compare "Actual cash value."
Single-limit insurance
An autmotive insurance policy with a single combined dollar limit of coverage for property damage, liability coverage and bodily inury coverage. Compare "split-limit insurance."
Split-limit insurance
A policy with separately stated dollar limits for different types of coverage. Bodily injury liability coverage is also usually split into a maximum payment per person and a maximum payment per accident. (For example, an automobile liability policy of 50/100/25 provides a maximum of $50,000 bodily injury coverage per person, $100,000 bodily injury coverage per accident, and a property damage limit of $25,000 per accident.) Compare "single-limit insurance."
Underwriter
A company that engages in insurance underwriting. See "Underwriting."
Underwriting
The process of evaluating the risk exposure to a potential insured (or class or category of insureds), whether to accept the risk and offer insurance coverage, and the premium to be charged for that coverage.
 

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Fuel/Economy/Impact

Air pollution score
A score from zero to ten given by the EPA to each new vehicle that represents the amount of air pollutants produced during a laboratory driving simulation of the vehicle.
AT-PZEV
Advanced technology-partial zero emission vehicle. An emissions standard that meets PZEV requirements and has additional zero-emissions characteristics, such as operation by natural gas or hybrid vehicle batteries.
Biodiesel blend
Also referred to as "biodiesel." A fuel that is a mixture of petroleum-based diesel and plant-based diesel.
Carbon dioxide
A naturally occurring "greenhouse gas" that is also a byproduct of the combustion of fossil fuels and that consists of two carbon atoms bonded to a single oxygen atom.
Carbon footprint
A measure of a vehicle's total consumption of natural resources weighed against the Earth's ability to regenerate those resources.
Carbon monoxide
A "greenhouse gas" that is a byproduct of the combustion of fossil fuels and that consists of a single carbon atom bonded to a single oxygen atom.
Certification sales region
A geographic area (usually identified by the states of which it consists) in which a specific vehicle is certified by the EPA to be sold to the public.
City fuel economy
The average number of miles a vehicle is able to travel using one gallon of fuel according to EPA simulated laboratory tests of city driving conditions.
Combined fuel economy
The average number of miles a vehicle is able to travel using one gallon of fuel according to EPA simulated laboratory tests that consist of 55% highway and 45% city driving conditions.
Deceleration fuel cut-off
A system that automatically cuts the fuel supply when coasting or braking in order to achieve better fuel efficiency and more effective engine braking, and resumes fuel supply when acceleration is once again needed.
Dual-mode hybrid
A hybrid vehicle with two different drive systems, referred to as Modes. In the first mode the vehicles runs solely on an electric motor powered by the vehicle's battery system. When the electric-only mode is low on power, or during harder acceleration and faster speeds, a gasoline engine mode will initiate. The second Mode uses a gasoline engine to help power the vehicle and recharge the electrical system batteries.
E85
A fuel consisting of gasoline or another hydrocarbon mixed with up to 85% denatured ethanol.
Emissions certification standards
Numerical limits on the pollutants produced by a vehicle established by the EPA and the California Air Resource Board.
Emissions score
A score from zero to 10 given by the EPA to each new vehicle that represents the amount of total emissions produced during a laboratory driving simulation of the vehicle.
Emissions standards
The maximum allowable levels of NOx, carbon monoxide, nonmethane organic compounds and particulate matter permitted by EPA regulations to be emitted by each new vehicle.
Engine Auto Stop/Start
A system that automatically shuts the engine off when a vehicle comes to rest for a period, and then restarts it automatically when the brake is released and the throttle is depressed.
Engine descriptor
A special notation attached to a vehicle's engine code in order to describe its emissions rating or its fuel economy, or that indicates that it can be run on multiple fuel sources.
Environmental impact
An assessment of the biophysical effects a vehicle has on the environment, commencing with its production and ending with its disposal.
EPA fuel economy/MPG estimates
The city and highway fuel economy ratings issued by the EPA.
EPA testing
Laboratory tests of new vehicles conducted by the EPA in controlled driving simulations, for the purpose of generating data on average fuel economy, air pollution and greenhouse gas production.
Estimated annual fuel costs
The estimated cost of fueling a vehicle over the course of a year, assuming 15,000 miles per year are driven and a price per gallon designated by the EPA.
Ethanol
Ethyl alcohol. A commonly used vehicle fuel.
EV
Electric vehicle.
EV effective range per charge
The average distance an electric vehicle is able to travel on a full charge, as measured by the EPA and listed on the vehicle's window sticker.
Flex fuel vehicle
A vehicle than can run on at least two different fuel sources either simultaneously through a single fuel system or separately through multiple fuel systems.
Fuel consumption
The rate at which an engine depletes its fuel supply.
Fuel economy
A measure of the amount of fuel used by a vehicle over a certain distance, or the distance traveled per volume of fuel used.
Fuel type
The type of fuel used to power a vehicle: gasoline, ethanol, E85, diesel, bio-diesel, natural gas or electricity.
Greenhouse gas score
A score from zero to 10 given by the EPA to each new vehicle by that represents the amount of greenhouse gases emitted during a laboratory driving simulation of the vehicle.
Greenhouse gases
Gases produced by vehicles that use hydrocarbons as fuel (such as carbon dioxide, carbon monoxide, methane, nitrous oxide and hydroflourocarbons) that contribute to reducing the loss of atmospheric heat into space.
Highway fuel economy
The average number of miles a vehicle is able to travel using one gallon of fuel according to EPA simulated laboratory tests of highway driving conditions.
Hybrid degree
The level of hybrid technology used for a vehicle: full, mild, power-assist or plug-in.
Hybrid drivetrain layout
The drivetrain layout in a hybrid vehicle: parallel, series or combined.
Hybrid power source
The source of power in a hybrid vehicle: gas/electric, plug-in, fuel cell or pneumatic.
Hybrid vehicle
A vehicle that combines the use of internal combustion and electricity as power sources.
Hydrocarbons
Organic compounds commonly used as a fuel source consisting of only hydrogen and carbon atoms.
Hydrogen fuel cell
An energy conversion device that produces electricity by means of electrochemical reactions between hydrogen and an oxidant.
ILEV
Inherently low-emission vehicle. An emissions standard for alternative-fuel vehicles with closed and pressurized fuel systems.
Intelligent alternator
An alternator that operates primarily when the engine has no need for power, i.e., when coasting or during braking. The alternator remains passive while the vehicle is under power, with needed electrical power provided by the battery, for the purpose of improving the vehicle's fuel efficiency.
LEV
Low emission vehicle. A vehicle that meets the average emissions standard within the LEV program.
LEV Program
See "Low Emissions Vehicle (LEV) Program."
Li-ion
Li-ion (Lithium-ion) battery is a type of rechargeable battery that offers better performance versus conventional rechargeable batteries such as NiCad (Nickel-Cadmium) and NiMH (nickel-metal hydride). Lithium-ion offers more power and less weight, which offers an extended driving range. However, Li-ion batteries are more fragile and can be damaged by extreme temperatures.
LNG
LNG (Liquefied natural gas) is natural gas (CH4) that has been refined and liquefied. The Process of liquefying natural gas requires the removal of contaminants like helium, water, and heavy hydrocarbons then condensed into a liquid state close to atmospheric pressure 3.6 psi (25 kPa) by cooling it to approximately -260 °F (-163 °C).
Low Emissions Vehicle (LEV) Program
The National Low Emissions Vehicle Program. An EPA-sponsored initiative to reduce the amount of emissions per vehicle.
LPG
Liquefied petroleum gas. Also referred to as "GPL," "LP Gas" or "autogas." A blend primarily of two hydrocarbon gases, propane and butane. Propylene and butylenes can also be present in small concentration. Ethanethiol, a powerful odorant, is also added so that leaks can be detected.
M85
M85 is a blend of 85% methanol and 15% gasoline. It is not commonly used because Methanol and Methanol fumes are poisonous.
MPG
Miles per gallon.
NLEV program
National low emission vehicle program. A voluntary national low emission vehicle program for light-duty vehicles and light-duty trucks that is enforced by the EPA (outside of California) once automakers and states opt in and the program is in effect.
NOx
An abbreviation for six chemical compounds produced during high temperature combustion, containing only nitrogen and oxygen atoms, that react with volatile organic compounds in the presence of sunlight to create photochemical smog.
Parallel hybrid
A vehicle that is powered by an electric motor and an internal combustion engine that are inline. This type of hybrid can be driven on either full electric mode, gasoline engine mode, or combined. This is the most common type of hybrid vehicle currently used today.
Plug-in vehicle
A vehicle powered solely by electricity available from a standard domestic AC power socket.
PZEV
Partial zero emission vehicle. A vehicle that has zero evaporative emissions and meets the EPA's SULEV standard.
Rear electric motor type
The type of rear electric motor in a hybrid vehicle or EV used to power the rear wheels: permanent magnet motor or other traction motor.
Regenerative braking
A method of assisting the deceleration of a hybrid or electric vehicle in which the vehicle's electric motor switches from drive/output mode to generator mode. This recharges the battery by converting a portion of the vehicle's kinetic energy into electrical energy.
Renewable energy
Natural energy sources that are naturally replenished, such as solar power, wind power, hydrogen and biofuels.
Series hybrid
An electric vehicle with a gasoline combustion engine that is only used to recharge the vehicle's batteries. The gasoline engine does not drive the wheels directly. An example is the Chevrolet Volt.
SmartWay
A designation issued by the EPA for new vehicles with a score of six or higher in both air pollution and greenhouse gas emissions and a combined total of more than 13.
SmartWay elite
A designation issued by the EPA given to new vehicles with a score of nine or higher in both air pollution and greenhouse gas emissions.
Smog-forming pollution
Pollutants in the hydrocarbon or NOx families that produce photochemical smog when combined in the presence of sunlight.
Solar power
Energy derived directly from the sun through photovoltaic cells or other devices that convert light energy into electricity or heat.
Solar sunroof
A sunroof with a photovoltaic panel infused into its glass that is used to power interior ventilation fans in order to lower cabin temperature when a vehicle is parked in the sun.
Start-stop system
A system typically found in hybrid vehicles that automatically stops and restarts the internal combustion engine to reduce the amount of time the engine spends idling and improve fuel economy.
SULEV
Super-ultra low emission vehicle. A vehicle that meets an emissions standard that is stricter than the ULEV standard.
Tier 1 EPA Program
The EPA's first vehicle emission program promulgated under the Clean Air Act of 1994, which set more stringent national vehicle emissions standards than had previously existed.
Tier 2 EPA Program
The EPA's second vehicle emission program promulgated under the Clean Air Act of 1994, which set more stringent national vehicle emissions standards than the Tier 1 EPA Program.
ULEV program
Ultra-low emission vehicle standard; an emissions standard within the LEV program, tighter than the LEV standard.
Underhood label ID
A label required by the EPA that is affixed to the underside of a new vehicle's hood to designate its engine family and EPA vehicle test group.
Well-to-wheel
See "Environmental impact."
ZEV
Zero emission vehicle. The most restrictive emissions standard.
 

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Maintenance

A/C compressor
An engine-driven pump in the air conditioning system that increases the pressure of the refrigerant.
A/C drain hose
A hose used to drain condensation from the air conditioner evaporator.
Accelerator pedal linkage
The linkage between the accelerator pedal and a vehicle's throttle body or carburetor.
ACE filter
Active cornering enhancement filter. A device used in an electro-hydraulic suspension system to reduce body roll by adjusting the system to driving conditions.
Air conditioner refrigerant
The liquid used in air conditioning systems, which has the property of boiling at ambient air temperatures.
Air conditioning filter
A device that removes contaminants from external air entering the ventilation system.
Air filter
A device that filters incoming air fed to the engine.
Air filter restriction indicator
A device that identifies an impedance to the air filter system.
Air pump filter
A device that eliminates contaminants from the air supply fed to the air injection system.
Antifreeze
See "Coolant."
Antilock brake system high pressure hose
The reinforced hose or hoses (with metal fittings at either end) that carry high pressure hydraulic fluid used in an antilock brake system.
ATTS
Honda's Automatic Torque Transfer System, which is a system that distributes an engine's torque output proportionately between the driven axles (so that the output is most effectively used).
ATTS unit fluid
Hydraulic fluid used in Honda's Automatic Torque Transfer System.
Auto shift lock/starter safety switch
A device that prevents the starter from functioning unless the shifter is in the park or neutral position, and prevents the shifter from being moved unless the brake pedal is depressed.
Automatic transaxle
A combination transmission and differential/drive axle assembly.
Automatic transaxle pressure filter
The external filter on an automatic transmission.
Automatic transmission bands
In an automatic transmission, adjustable circular straps lined with a friction material that are actuated to tighten around and stop the rotation of a drum as part of the shifting process.
Automatic transmission cooler hoses
Flexible tubes that carry transmission fluid to and from a heat exchanger or oil cooler.
Automatic transmission filter
A component in most automatic transmissions that is fitted over the fluid intake, usually in the pan, that prevents debris and other contaminants from circulating throughout the transmission's inner workings and potentially causing unnecessary wear or damage. Some transmissions use a reusable metal or nylon mesh-type screen in place of a disposable filter.
Automatic transmission fluid
The fluid used for lubricating and cooling an automatic transmission.
Axle drive fluid
The liquid used for lubricating gears inside the axle.
Balance shaft belt
A cogged belt that drives a shaft (usually in synchronization with the engine's crankshaft) for the purpose of smoothing out vibrations.
Ball joints
Movable joints in the steering linkage and suspension system of a vehicle that permit rotating movement in any direction between the parts that are joined.
Bi-level purge valve
In an evaporative emissions system, a valve that limits the flow of vapor from the charcoal canister to the intake during idling.
Body
The outer panels that shroud the mechanical and electrical workings of a vehicle.
Body water drains
Drain holes in strategic locations that provide an escape route for water that would otherwise remain trapped within a vehicle's body.
Brake booster
A vacuum-based device that amplifies the foot pressure applied to power brakes.
Brake booster bellcrank pivot
The linkage pivot points behind some brake boosters.
Brake fluid
The fluid used in the hydraulic brake system.
Brake lines, hoses & connections
Tubes and their connections that carry brake fluid between the various components in a vehicle's brake system.
Brake linings
High-friction, heat-resistant material that is attached to the brake shoes in a rear drum brake system.
Brake master cylinder
A device that stores brake fluid and hydraulically forces it through the brake lines to the brakes when the brake pedal is depressed.
Brake pads
High-friction material attached to a metal backing plate.
Brake pedal
A device used to control a vehicle's brakes.
Brake pedal spring
A spring attached to the pedal assembly that provides some resistance during pedal depression and also assists in returning the pedal to an upright position.
Catalytic converter
A canister in the exhaust system, usually situated before the muffler, containing a substance that reacts chemically with the exhaust in order to reduce harmful emissions.
Catalytic converter heat shield
A metal panel, which may be insulated, that is used to prevent the catalytic converter heat from harming surrounding areas.
CCV
See "Crankcase ventilation filter."
Charcoal canister
A device that captures raw fuel vapors (hydrocarbons) from the vehicle's fuel tank and carburetor bowl before they can escape into the air.
Choke linkage
On a carbureted engine, the assembly of parts that controls a valve that limits incoming cold air until the engine reaches operating temperature and is able to more efficiently vaporize fuel.
Climate-controlled seat filter
Air filter for air-conditioned seats.
Clutch bushing & linkage
The parts of the mechanical connection between the clutch and clutch pedal in a non-hydraulic clutch system.
Clutch fluid
The liquid used in a hydraulic clutch system that helps disengage the clutch from the flywheel.
Clutch fork ball stud
The pivot point for the clutch fork in the clutch housing of a manual transmission.
Clutch lines & hoses
In a hydraulically actuated clutch, the tubes that carry fluid between the clutch master cylinder and the slave cylinder.
Clutch master cylinder
In a manual-transmission vehicle with a hydraulically actuated clutch, a small-bore hydraulic cylinder mechanically connected to the clutch pedal that actuates a slave cylinder, which in turn actuates the clutch fork that disengages the clutch when the clutch pedal is depressed.
Clutch pedal
A pedal located on the floor of the vehicle to the left of the brake pedal that, when depressed, disengages the clutch from the flywheel.
Coolant
Also known as "antifreeze." A mixture of water and ethylene glycol that has both a higher boiling point and a lower freezing point than plain water.
Cooling fan & shroud
A mechanically, hydraulically or electrically driven fan that pulls cooling air through a vehicle's radiator; the shroud forms a direct passage between the radiator and fan, improving the fan's effectiveness.
Crankcase breather
A ventilation system or device that allows excessive crankcase pressure to escape.
Crankcase depression regulator valve
A valve that prevents excess pressure from building in the crankcase (which could lead to oil leakage past the seals).
Crankcase ventilation filter
Also known as the "CCV." A filter that prevents foreign particles from entering the crankcase.
CV joints
Constant velocity joints, which are located on either end of the drive axles and transmit engine power while enabling full steering and suspension movement. Black accordion boots cover and protect these joints and hold lubricant.
Cylinder head bolts
Bolts that clamp an engine's cylinder heads to the engine block.
Deceleration system
An emissions device on a manually shifted vehicle that bleeds vacuum from the intake when the vehicle is in gear with the throttle closed. This causes the fuel injectors to close during conditions of deceleration and results in reduced emissions.
Declutching/freewheeling
The act of disengaging a vehicle's transmission from its driveshaft, either manually or automatically, when its driveshaft's rpm exceeds the transmission's rpm.
Differential fluid
The liquid used for lubricating gears inside the differential.
Distributor cap
The nonconductive cap of the distributor that contains the contacts leading to each individual spark plug.
Distributor rotor
The rotating, nonconductive component of a distributor that contains contacts and that, when aligned, complete an electrical circuit between the ignition coil and a spark plug.
Diverter valve
On an engine equipped with an air pump, a valve activated during deceleration that allows air from the air pump into the intake to dilute the air/fuel mixture (in an attempt to reduce emissions).
Downshift cable
A transmission cable connected to the throttle that shifts the transmission into a lower gear when the accelerator is depressed suddenly beyond a certain point.
Drain plug washer
A composition or plastic sealing washer used on a bolt-type drain plug.
Drive axle boots
The flexible, conical, accordion-like covers that contain lubricant and protect the constant-velocity joints on a drive axle shaft.
Drive belt tensioner
A self-adjusting device used for maintaining proper tension on the drive belt.
Drive belt(s)
A belt that transfers the rotation of the engine through the crankshaft pulley to drive various devices, such as the alternator, water pump, air conditioning compressor or power steering pump.
Drive shaft
A sturdy metal tube with universal joints on either end that connects the engine to a differential on a rear-wheel or four-wheel drive vehicle.
Drive train mounts
Flexible, energy-absorbing components that attach parts of a vehicle's drive train (for example, the transmission, transfer case or differential housing) to the chassis.
EGR system
Exhaust Gas Recirculation system. A device that redirects a small amount of exhaust to the engine intake in an effort to lower combustion temperature and reduce the emission of nitrogen oxide.
Emissions hoses & tubes
Hoses and tubes utilized by any of a vehicle's emission control devices.
Engine oil
A substance that lubricates and cools the moving parts of the engine and reduces corrosion and the formation of rust.
Engine oil level warning system
A device that automatically brings a low engine oil level to the attention of a driver.
Engine thermostat
A device that senses the temperature of the engine coolant for the purpose of regulating the engine cooling system.
Evaporative control canister
A device that captures raw fuel vapors (hydrocarbons) from a vehicle's fuel tank and carburetor bowl before they can escape into the air.
Evaporative control canister filter
A filter on the evaporative control canister that filters incoming air as fuel vapors contained in the canister are being drawn back into the engine.
Evaporative control system
An emission control system that prevents raw fuel vapors from entering the atmosphere.
Exhaust pressure regulator valve
A device that directs warm exhaust to a vehicle's intake in an effort to aid fuel vaporization and reduce warm-up time.
Fan hub
The mechanical connection between the radiator fan and its point of attachment.
Fuel filler cap
A cap used to seal a vehicle's fuel filler neck.
Fuel filter
A replaceable metal or plastic canister that prevents particulate matter and most contaminants in the fuel from reaching the engine.
Fuel lines & connections
The tubing and connections that carry fuel through a vehicle.
Fuel pre-filter
For diesel-fuel engines, the device that filters the fuel immediately before it enters the fuel pump.
Fuel system
The assemblage of parts that stores and delivers fuel for the engine, including the fuel cap, fuel tank, fuel lines and hoses, fuel pump, fuel filter and fuel injectors or carburetor.
Fuel/water separator
A device that separates the water from the fuel in addition to, or as part of, the fuel filtering system.
Haldex clutch
Limited slip coupling used in vehicles with automatic all-wheel drive systems to engage and disengage a secondary axle when needed.
Heated air temperature sensor
A device that provides information needed by a vehicle's computer to determine the temperature of the air coming into the engine.
Heater hoses
Tubing that carries engine coolant between a vehicle's cooling system and heater core.
Idle speed
The RPM of the engine free from load (all accessories off), at normal operating temperature and in neutral (or, in the case of an automatic transmission, park or neutral).
Idler pulley
A guide or tightening pulley for a belt or chain.
Ignition timing
The process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity.
Kingpin bushings
Lubricated solid bearings or bushings usually present between the kingpin and steering knuckle.
Lock cylinders
The part of a hatch or door's latching mechanism into which the key is inserted.
Manifold heat control valve
A thermostatic device that routes exhaust heat to the intake manifold in order to promote fuel vaporization and reduce warm-up time.
Manual transmission fluid
The fluid used for lubricating and cooling a manual transmission.
Oil filter
A cartridge-filled canister placed in an engine's lubricating system to strain dirt and abrasive materials out of the oil.
On-board diagnosis system
A computer-controlled system that identifies malfunctioning or out-of-adjustment components under its control through the display of trouble codes. The presence of trouble codes is usually indicated by an intermittently or constantly lit "check engine " or "service engine soon" light.
Overpressure safety switch
A switch used on a turbocharged engine that warns the operator of excessive and potentially harmful intake pressure that may be caused by component malfunction.
Oxygen sensor
In a computer-controlled, fuel-injected vehicle, a sensor mounted in the exhaust stream that relays air/fuel ratio information to the fuel control computer that allows the computer to make adjustments.
PCV filter/PCV valve
Positive crankcase ventilation filter/positive crankcase ventilation valve. Devices that allow the venting of combustion gases from the crankcase to the intake system instead of into the atmosphere.
Pilot bearing
A bearing that is press-fit into the rear of the crankshaft and that supports the tip of the transmission input shaft.
Plenum chamber water drain valve
A valve used on some vehicles to drain collected condensation from the intake plenum.
Power steering fluid
Hydraulic fluid used in a power steering system.
Power steering hoses
The flexible hoses carrying hydraulic fluid between the various components of a power steering system.
Purge valve
In an evaporative emissions control system, the valve that allows the venting of fuel vapors from the charcoal canister to a vehicle's intake and prevents the canister from becoming saturated and nonfunctional.
Radiator core & AC condenser
The part of a vehicle's radiator and air conditioning systems made up of small-diameter tubes with a series of thin, heat-conducting fins in between.
Radiator hoses
The tubes between the radiator and the engine.
Secondary air supply system
A type of emissions-reducing system that promotes the combustion of unburnt hydrocarbons in the exhaust stream by introducing oxygen (fresh air) pulled in by a vacuum created by exhaust pulsations (and which essentially performs the same function as an air injection system without relying on an air pump or diverter valve).
Self leveling suspension (SLS) filter
Sometimes referred to a an "SLS filter." A device used to remove contaminants from hydraulic fluid in a self-leveling suspension system.
Serpentine belt
A ribbed drive belt that drives more than one engine accessory.
Service reminder light
A light that indicates that general vehicle maintenance is needed or that a specific service is required.
Shields and under-hood insulation
Heat-proof panels and padding that protect under-hood components from excessive heat.
Shift linkage
Any collection of mechanical connections between a vehicle's operating control(s) and its transmission.
Spark plug wires
Cables that carry a high-voltage electrical charge from the distributor cap or ignition coils to the spark plugs.
Stabilizer bar
Sometimes called an anti-roll or anti-sway bar. A device that connects the left and right sides of a suspension to limit body roll in turns.
Starter safety switch
An electrical switch that prevents the starter from being engaged unless certain conditions are met, such as shifter placement or brake pedal depression.
Steering column lock
A mechanism that prevents steering wheel movement unless the ignition switch is moved from the locked position.
Steering damper
A shock absorber attached to the steering linkage intended to prevent abrupt "kickback" at the steering wheel, usually found on trucks or vehicles that can be used off-road.
Steering gearbox
A steering mechanism that converts the rotational motion of a steering wheel to the side-to-side motion of a lever that is connected to the steering linkage.
Steering intermediate shaft
A component in the steering system that connects the steering shaft to the steering mechanism.
Steering knuckle
The pivoting component to which the front wheel hubs are attached.
Steering linkage
The arrangement of rods and lubricated joints connecting the steering gearbox to the wheel spindles.
Steering rack
The steering component that converts the rotational motion of the steering wheel to the horizontal motion necessary to operate the steering linkage.
Supercharger drive belt
A "toothed" belt used to drive a pulley that turns the impeller of a centrifugal-style supercharger.
Supercharger fluid
A liquid used to lubricate the internal components (for example, the impeller and the bearings) of a supercharger.
Suspension fluid
A fluid used in suspension systems that are hydraulically adjustable.
Thermostatically controlled air cleaner
A device on carbureted engines to control emissions, which contains a thermostat-controlled diverter that ducts air warmed by the exhaust manifold to the carburetor during cold conditions, and then ambient air to it once a certain temperature has been attained. This enables the engine to reach a normal operating temperature and end its fuel-rich/inefficient cold-temperature mode as quickly as possible.
Throttle & kick down lever ball studs
Lubricated pivot points for the throttle or kickdown linkages.
Throttle linkage
A collection of mechanical connections between a vehicle's accelerator pedal and its throttle body or carburetor.
Throttle system
The components used to control the volume of air to the engine.
Tie rod ends
Ball and socket parts of the steering linkage that connect the wheel spindles to the rack and pinion or center link.
Timing belt
A "toothed" belt that drives an overhead camshaft or camshafts (and in some vehicles a water pump).
Timing belt tensioner
A spring-loaded idler wheel that automatically keeps the timing belt under enough tension to prevent the timing belt from allowing the camshaft(s) it controls to go out of sync.
Tire inflator
A device used to inflate, or inflate and seal, a collapsible spare or flat tire.
Tire inflator sealant cartridge
A disposable container of pressurized sealing compound.
Trailer hitch mountings
Trailer hitch attachment points on the body or chassis.
Transaxle
A combination transmission and differential/drive axle assembly.
Transfer case fluid
Lubricant used in the transfer case.
U-joints
Universal joints, which are flexible joints used on drive shafts that are composed of two U-shaped yokes that share a common cross-shaped member.
Underbody
The area of a vehicle that is typically not visible from above and that is exposed to the road.
Vacuum lines & hoses
Flexible tubing used to carry air, fluids, vapors or pressurized gas.
Valve clearance
The maximum amount of space between a rocker arm or cam and the part it contacts to actuate a valve.
Variable gear ratio steering assembly
The steering mechanism that converts the rotational motion of a steering wheel to the side-to-side motion of a lever that is connected to the steering linkage.
Water pump
A device that circulates coolant through a vehicle's cooling system.
Water pump weep hole
A small orifice on a water pump behind and below the exposed end of the shaft.
Weather strip
The rubber stripping around a vehicle's doors and hatches or their portals.
Wheel alignment
The adjustment of various components to meet predetermined specifications for camber, caster, toe and ride height.
Wheel bearings
The assemblies that permit smooth rotation between the wheel hub and spindle.
Wheel cylinders, rear
In drum-type brakes, small-bore hydraulic cylinders that are fitted between the brake shoes and are actuated when the brakes are applied.
Wheel lug nuts/bolts
The nuts that hold a wheel onto its hub.
Wheel speed sensor wiring
Electrical connections of the system that relay the speed of each wheel to a computer that makes adjustments in brake application to prevent wheels from locking up.
Wideband oxygen sensor
A faster, more sensitive oxygen sensor that enables an engine control unit to make changes to the air/fuel ratio more rapidly and precisely than with a conventional sensor.
Wiring harness
The groups of wires and connectors that carry electric current through the vehicle.
 

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Performance

Adjustable suspension
A suspension that offers driver-selectable damper (and sometimes spring) firmness settings to suit varying conditions and personal preferences.
Auto-leveling suspension
A suspension that adjusts the height of the vehicle so that its rear stays even with the front when cargo is carried; some systems offer multiple height settings for off-road, normal and high-speed operation.
Drivetrain
The system of components that generates power and transmits it to a vehicle's wheels.
Engine performance
An engine's ability to do work in terms of horsepower, torque or efficiency.
Forced induction
The forced compression of air into an engine's cylinders by means of a supercharger or turbocharger.
Four-wheel steering
A feature of some vehicles that allows the rear wheels to be steered (by a computer and actuators), for the purpose of increasing high-speed cornering stability.
Horse Power
A unit of measurement for engine power that was originally developed as a way to express the output of steam locomotives in terms of the strength of draft horses.
Hybrid performance
A hybrid engine and electric motor's combined ability to do work in terms of horsepower, torque or efficiency.
Instrumented testing
The analysis of a vehicle's performance characteristics using precise scientific equipment.
Max HP RPM
The speed of an engine at which it generates its maximum horsepower.
Max Torque RPM
The speed of an engine at which it generates its maximum torque.
Number of speeds
The number of different drive ratios a vehicle's transmission is capable of selecting.
RPM
Revolutions per minute.
Shift protocol
The means by which a driver changes gears, including buttons, paddles or a lever.
Supercharger
A device powered by a belt, gear, shaft or chain connected to the engine's crankshaft that forces air into an internal-combustion engine in order to increase engine power.
Torque
A measurement of an engine's power that indicates how forcefully it can rotate the crankshaft at a given engine speed.
Transmission modes
Driver-selectable transmission settings that change drive ratios and/or shift points for fuel economy or performance.
Transmission overdrive
A final gear ratio for an automatic transmission that has an output speed greater than its input speed, which increases highway fuel economy.
Transmission type
The type of transmission: automatic, manual, shiftable automatic or automated manual.
Turbocharger
Sometimes referred to as a "turbosupercharger." A device that uses an exhaust-driven turbine to force air into an internal-combustion engine in order to increase engine power.
Valves per cylinder
The total number of intake and exhaust valves employed in each individual cylinder of an engine.
 

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Pricing and Incentives & Rebates

Acquisition fee
Also known as a "bank fee," an "administrative fee" or an "assignment fee." For a vehicle lease, a fee charged by the leasing company at the inception of the lease that is intended to cover a variety of administrative costs, such as obtaining a credit report, verifying insurance coverage, checking the accuracy and completeness of the lease documentation, and entering the lease into its data and accounting systems.
Administration fee
See "Acquisition fee."
Aftermarket accessory
An accessory or piece of equipment that is not included in the vehicle as manufactured, but is purchased and installed at the dealership or other automotive establishments.
APR
Annual Percentage Rate. The cost of credit (i.e., the interest rate) expressed as a yearly rate.
Asking price
The price for a vehicle asked (before any negotiations) by the dealer or other seller.
Assignment fee
See "Acquisition fee."
Bank fee
See "Acquisition fee."
Base price
The MSRP of a vehicle before options, destination fee, any dealer advertising fee and other costs.
Buyout amount
See "Payoff Amount."
Cap reduction
Capital reduction. In a vehicle lease, any trade-in amount, cash down payment or rebate amount that reduces the cost of the vehicle being leased (its "capitalized cost").
Capitalized cost
Often called the "cap cost." The negotiated price of a vehicle to be leased, and one of the components used to determine the monthly lease payment.
Captive finance company
An automobile lender that is a subsidiary of an automobile manufacturer and whose principal business includes financing the sales and/or leases of that manufacturer's vehicles.
Cash rebates
Rebates provided by the manufacturer directly to the customer at the time the vehicle is purchased to lower the final price of the vehicle. Consumers usually may elect to either receive this amount in cash or to credit the rebate as part of the vehicle's down payment.
Closer
An experienced dealership salesman or sales manager who attempts, towards the end of the negotiation process, to either improve the deal for the dealership or to persuade a hesitant buyer to commit to the purchase.
Credit score
A number (referred to as a "score"), prepared by a company in the business of scoring individuals' creditworthiness or in accordance with algorithms it has established, that represents a judgment as to the individual's creditworthiness and which is based on an analysis of data reflected in his or her credit report and other personal information.
Credit tier
The credit "category" in which a consumer is placed by credit-rating companies, based on the consumer's personal credit history. A consumer's credit tier helps predict how financial institutions will view that consumer as a financial risk (i.e., the likelihood that he or she will make payments on time and ultimately repay the loan). Edmunds.com uses five tiers: platinum, gold, silver, bronze and unclassified. For more information, visit http://www.edmunds.com/tmv/about_finance.html.
Credit union
A financial institution that is owned by its account holders, membership of which is based on specified criteria (for example affiliation with an employer or union).
Customer cash incentive
A cash payment made by the manufacturer of a vehicle to a customer to incentivize its purchase.
Dealer cash incentives
Amounts that are paid to dealers by manufacturers to stimulate vehicle sales by incentivizing the dealers to lower their prices to consumers, typically paid or earned upon the dealer's purchase of the vehicle from the manufacturer, upon the dealer's sale of the vehicle, or when the dealer achieve specified sales volume targets.
Dealer holdback
A percentage of either the MSRP or invoice price of a new vehicle (depending on the manufacturer) that is repaid to the dealer by the manufacturer after the vehicle is sold. For more information, read this article on dealer holdback.
Depreciation
The amount by which a vehicle (or any physical item) loses its value over time. In vehicle lease transactions, the projected depreciation of the vehicle is used to determine the vehicle's projected residual value and the monthly lease payments.
Destination charge
The fee that the manufacturer charges to deliver a vehicle from the factory to the dealership, and that is passed on by the dealer to the consumer; it is not included in the MSRP of the vehicle. The destination fee is the same for a particular vehicle no matter where the dealership is located (with the exception of Alaska and Hawaii in some instances).
Disposition fee
An amount charged by the leasing company at the end of a lease that is intended to cover the cost of retrieving and selling the vehicle if the lessee chooses not to buy it. The lessee is billed for this charge after the vehicle is returned.
DMV fees
Department of Motor Vehicle fees. Sometimes referred to as "title and license fees." The fees payable to the state in which a vehicle is purchased and/or registered, primarily for vehicle titling, registration and license plates.
Down payment
A cash payment credited against the purchase price of a vehicle, which reduces the amount to be financed. In a lease transaction, this amount is often referred to as the "capital reduction."
Drive-off fees
Also referred to as "Total Due at Signing." The total cost that must be paid by the lessee at the inception of a vehicle lease, which typically includes the first month's lease payment, any security deposit required by the leasing company, any acquisition fee charged by the leasing company, any documentation fees charged by the dealer, and various state registration fees.
Early termination
Ending a vehicle lease before its original term has expired.
Equity
For a vehicle that has been financed through a loan, the difference at any time between what a vehicle is worth at that time and the amount that is then owed on the loan.
Excess mileage penalty
A fee the lessee must pay when the allotted miles specified in the lease are exceeded. The fee is customarily $0.12-$0.25/mile in excess of the allotted miles.
Excess wear and tear
Wear or damage to a vehicle that is in excess of what is normally expected in the ordinary course of operating a leased vehicle.
Factory-installed
Vehicle equipment that is installed by the manufacturer (in contrast to equipment that may be installed by the dealer or the owner).
FICO
Fair Isaac Corporation, which is a company that calculates and distributes consumer credit scores.
Finance
To borrow money (either as a loan or in the form of a lease) to obtain some or all of the funds to acquire a vehicle.
Finance and insurance office
Sometimes referred as the "F&I office." The office within a dealership in which vehicle purchase contracts are prepared and signed and additional services (including insurance and extended warranties) may be offered to the purchaser.
Finance incentive
Manufacturer loan programs offered to consumers, usually for a limited period, on selected vehicles and/or in certain areas, as an incentive to purchase a vehicle.
Finance rate
See "APR."
Four-square worksheet
A standard form used at many dealerships that helps salespeople keep track of four elements of a deal during negotiations with a customer: the price of the vehicle, the amount to be credited for the trade-in, the down payment and the monthly payment.
Gas guzzler Tax
A graduated federal tax levied at the time of initial new-vehicle purchase on vehicles with especially poor fuel economy.
Incentive
Any kind of financial assistance from a vehicle manufacturer that, by reducing either the net price or the cost of financing/leasing, motivates customers to buy/lease a new vehicle. The most common incentives are customer cash rebates, low-interest financing and leases that are subsidized by the manufacturer.
Incentives and rebates
An auto industry term that encompasses all methods by which manufacturers attempt to stimulate vehicle sales and leases by reducing the net cost to consumers without reducing the vehicles' MSRPs, which includes customer rebates, dealer cash incentives and special leases.
Invoice
Also referred to as "Invoice Price." The price that appears on the invoice that the manufacturer sends to the dealer when the dealer receives a vehicle from the factory. More information on invoice price.
Lease factor
See "Money factor."
Lease fee
See "Money factor."
Lease incentive
An incentive offered by the manufacturer to reduce the cost of a vehicle lease, either by reducing the interest rate or increasing the residual value of the vehicle.
Lease term
The number of months that constitute the term of a vehicle lease.
Lessee
The person or entity that leases a vehicle.
Lessor
The entity that owns the vehicle being leased. Although most leases are arranged by a dealership, in almost all cases the lessor is either a financial institution or a division of the vehicle manufacturer.
Low-interest financing
A loan offered by the manufacturer's captive finance company at a below-market interest rate.
Marketing support
An auto industry term that describes programs that manufacturers provide to stimulate sales or assist dealers in the advertising and marketing of their vehicles.
Mileage allowance
In a vehicle lease, the number of miles the lessee is permitted to drive over the term of the lease without incurring an excess mileage penalty.
Money factor
Also referred to as a "lease factor" or "lease fee." An auto leasing industry term for expressing the interest rate used to calculate the monthly lease payment, and equal to the lease's APR divided by 2,400. (For example, an APR of 7.2% equals a money factor of 0.0033.)
Monroney sticker
Also referred to as a "Window sticker." A sticker, required by law for all new vehicles sold in the United States, that is affixed to the side window or windshield and that must include the following information: MSRP, engine and transmission specs, standard equipment and warranty details, optional equipment and pricing, city and highway mileage ratings as determined by the Environment Protection Agency, and crash test ratings from the National Highway Traffic Safety Administration.
Monthly payment
The amount of principal and interest that must be paid each month under the terms of a finance or lease contract.
MSRP
Manufacturer's suggested retail price. Also referred to as "sticker price."
Payoff amount
Also called the "buyout amount." The amount that, at any specified time during the term of a vehicle lease or loan, is required to be paid in order to discharge the remaining obligation.
Private party price
The price consumers are paying private sellers for similar vehicles.
Purchase option
The right given to a vehicle lessee to purchase the vehicle at the end of the lease term for an amount equal to the vehicle's residual value.
Rebate
A cash payment offered as an incentive by the manufacturer to consumers, which is usually applied by the consumer to reduce the net price of a vehicle.
Residual value
A vehicle leasing company's assumption of what a vehicle will be worth at the end of the lease, which is a factor used to determine the monthly lease payment. (The higher the residual value, the lower the monthly payment.)
Security deposit
A payment required at the inception of a vehicle lease to provide collateral to the leasing company for the lessee's promise to comply with the terms of the lease.
Special lease
Also referred to as a "subsidized lease" or "subvented lease." A form of "incentive and rebate" that consists of a vehicle lease offered by a vehicle manufacturer in which the amount of the monthly payment is reduced below that then offered by independent leasing companies (the cost of which is absorbed by the manufacturer). Typically this is accomplished by using a higher residual value or a lower interest rate, or both.
Spiff
A cash incentive, contest entry or prize given by a dealership to salespersons as motivation to sell vehicles.
Sticker price
See "MSRP."
Subprime
A loan made to a borrower with a low credit rating and that typically bears interest at a higher rate to compensate the lender for the greater risk.
Subsidized or subvented lease
See "special lease."
Title
Sometimes referred to as the "pink slip." The legal document issued by the state in which the vehicle is purchased that reflects the person or entity registered with the state as its legal owner.
Total due at signing
See "drive off fees."
Trade-in
A vehicle that is currently owned by the purchaser of a new or used vehicle from a dealer and that is exchanged for the newly purchased vehicle in order to reduce its net price.
Upside-down
The status of a vehicle loan when the loan amount is greater than the current value of the vehicle.
Wholesale value
The price at which dealers purchase vehicles from other dealers or from lenders, usually at auction.
Window sticker
See "Monroney sticker."
 

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Safety & Crash Test

ABS
Antilock braking system. A computer-controlled system that prevents brakes from locking up and tires from skidding during hard braking.
Active pedestrian protection system
An electronic system designed to warn drivers of impending pedestrian traffic.
Adaptive cruise control
A laser- or radar-sensing cruise control system that causes a vehicle to automatically slow or stop in order to avoid front-end collisions.
Adaptive headlights
Headlights that turn as the driver turns the steering wheel, for the purpose of improving illumination in the direction of the turn.
Airbag deactivation
A system that uses sensors in a vehicle's front passenger seat to determine whether to activate that seat's front airbag, based on whether it detects the presence of an individual of sufficient weight.
Airbags
A cushion that deploys and fills with air when a major impact occurs to reduce a vehicle occupant's chances of coming in contact with the vehicle's interior surfaces.
Anti-theft
A device or system of devices that aid in preventing a vehicle from being stolen.
Anti-theft alarm
A device that uses an auditory signal and/or telemetric to alert a vehicle's owner of an attempted theft.
Anti-theft codes
A four- to six-digit numerical key necessary to return functionality to a vehicle's audio head unit after it has been removed or disconnected from the battery.
Anti-theft immobilizer
An electronic device that works together with a key (that includes a small transmitter) and that prevents the engine from starting when the key is not present.
Anti-theft remote control
An electronic device that unlocks a vehicle's doors and, in some cases, opens its trunk, rolls down its windows and opens and closes its sunroof.
Auto-delay headlights
A feature that keeps the headlights on for a period after a vehicle is shut off to provide the occupants with light as they walk away from the vehicle.
Auto dimming rearview mirror
See "Electrochromatic rearview mirror."
Automatic door unlock
A device that automatically unlocks a vehicle's doors after a collision.
Awareness aids
Electronic devices designed to keep a driver awake and alert while driving a vehicle.
Backup assistance
A device or system of devices (usually a park distance sensor or a back-up camera) designed to aid a driver's control of a vehicle in reverse.
Battery disconnect
A device that automatically disconnects a vehicle's battery after a collision.
Brake drying
A system that dries the brake pads through light friction just before a full stop is initiated, by using the ABS pump to bring the brake pads close to the rotors without significantly engaging them.
Braking assist
A system that monitors the swiftness of a driver's brake pedal application and applies additional braking force if it determines a that panic stop is occurring.
Brush guard
A metallic, tubular attachment to the front bumper of a vehicle that shields and protects the vehicle from plant life when driven off-road.
Caliper configuration
A description of the number of hydraulic pistons used in a vehicle's brake caliper and their arrangement in relation to each other.
Caliper type
The type of brake caliper: monoblock, sliding or dual sliding.
Center of gravity
A hypothetical point at which all of the mass of an object acts as if it were concentrated. For a vehicle, the lower the center of gravity the less likely the vehicle will be to roll over when it is destabilized.
Child seat
An additional seat and harness specifically designed for the safety of small children and designed to work with a vehicle's built-in restraint system.
Child seat
An additional seat and harness specifically designed for the safety of small children and designed to work with a vehicles built-in restraint system.
Childproof safety feature(s)
The option(s) to disable a vehicle's windows, door locks and/or passenger air bag in order to prevent injury to children.
Collapsible steering column
A steering column that collapses in the event of a hard frontal impact to reduce the risk of injury to the driver.
Cornering brake control
A feature of some antilock brake systems that proportions and applies brake force in order to prevent oversteer.
Cornering lights
A pair of white driving lights located at the two front corners of a vehicle designed to aid during cornering.
Crash test ratings
Ratings that represent a vehicle's performance in various crash tests, published by the organization(s) that conduct such tests.
Crumple zone
A section of a vehicle's structure that collapses during impact to absorb energy.
Curtain airbags
Also known as "head airbags." Wide-spanning airbags that when deployed cover the side glass in a side impact or, in some applications, a rollover, to keep occupants' heads and limbs fully inside the vehicle.
Death brake
A system of devices, including a heart rate sensor, that applies braking when the driver's heart stops beating.
Descent control
An off-road version of cruise control that uses the ABS and traction control systems to independently manipulate a vehicle's four brakes, which allows the driver to descend steep and uneven terrain at a walking speed more effectively than the driver can by using a break pedal that controls all four brakes at once.
Disc brake type
The type of brake rotors: solid, vented, slotted, cross-drilled, ceramic or carbon.
Driver state sensor
A device that monitors a driver's eye movement and/or vital signs while a vehicle is in motion.
Driving lights
Auxiliary high-beam driving lamps.
Dusk-sensing headlights
A feature that, when activated, automatically turns on the headlights and taillights when the ambient light dims at sunset.
Dynamic brake control
See "Emergency brake assist."
Electrochromatic rearview mirror
A rearview mirror that automatically dims at night when it detects a bright glare.
Electronic brake force distribution
A feature of some antilock braking systems that proportions and applies brake force to each wheel independently.
Electronic stability control
See "Stability control."
Emergency brake assist
An electronically controlled system that maximizes brake efficiency during panic stops.
Emergency braking preparation
A system that uses the adaptive cruise control sensors to monitor the following distance to the car ahead; if the gap is closing sufficiently quickly, in anticipation of a panic stop the system will cause the ABS pump to pre-fill the brakes and will bring the brake pads close to the rotors.
Emergency Trunk Release
A glow-in-the dark pull handle inside a car's trunk that permits escape for someone trapped inside.
Entry lighting
A system of lights that aids a driver or passenger in entering a vehicle in the dark.
ESC
See "Stability control."
Exterior camera
A video camera mounted outside a vehicle that relays its signal to a monitor within the cabin.
Fog lights
A pair of driving lights that provides a wide, low beam in an attempt to undercut fog.
Fuel pump shutoff
A device that automatically shuts off a vehicle's fuel pump after a collision.
Head airbags
See "Curtain airbags."
Headlight washers
A set of washer nozzles and/or wipers that clean a vehicle's headlights.
Headlights
A pair of bright lamps that provide visibility during darkness.
Heated mirrors
Sideview mirrors with internal electronic heating coils designed to prevent fog and ice from obstructing visibility.
Hill holder
A device that applies brake pressure when a vehicle's clutch is disengaged.
Inboard brakes
A braking system that is located within the chassis of a vehicle instead of at its hubs.
Insurance Institute for Highway Safety
Sometimes referred to as the "IIHS." An organization created by the insurance industry for the purpose of reducing the losses (deaths, injuries and property damage) from vehicle crashes.
Integrated turn signal
A turn signal light that is mounted on or in a vehicle's sideview mirror.
Intelligent car
A vehicle that employs the latest in telemetrics, driver awareness and/or pedestrian safety technology.
Knee airbags
Small airbags that deploy under the dashboard by the knees, typically on the driver's side where the steering column and other hard vehicle parts are located.
Lane departure warning system
A system of electronic components designed to warn a driver when a vehicle strays out of its lane.
Locks
A device or system of devices that prevents a vehicle from being entered without a key or an electronic keyless entry remote control.
Manual extending mirrors
A sideview mirror that can be manually moved further away from a vehicle when it is towing an object.
National Highway Traffic Safety Administration
Sometimes referred to as the "NHTSA." An agency of the United States government authorized to order manufacturers to recall and repair vehicles, or vehicle equipment, when investigations indicate that they contain serious safety defects in their design, construction or performance.
NHTSA campaign ID number
The identification number assigned to a recall by the National Highway Traffic Safety Administration.
NHTSA item number
The identification number assigned to a technical service bulletin by the National Highway Traffic Safety Administration.
Nightvision
An exterior camera that uses infrared technology to provide added visibility when driving in the dark.
NVH dampening
A system of devices that lessens the noise, vibration and harshness in the passenger compartment of a vehicle.
Office of Defects Investigation
An office within the National Highway Traffic Safety Administration that conducts defect investigations and administers safety recalls, and that monitors the adequacy of manufacturers' recall campaigns.
Oversteer
A handling characteristic of a vehicle that causes it to turn more sharply than the driver intends because the rear wheels are sliding to the outside of the turn.
Parking assist
An electronic system that employs laser, radar or sonar technology to enable a vehicle to park itself, in some cases without driver input.
Parking lights
Sometimes referred to as "daytime running lights." White lights intended to increase a vehicle's visibility to other drivers.
Parking senors
Button-size sensors in the front and/or rear bumpers that measure the distance to nearby cars and other objects and alert the driver using sounds or lights.
Polarization coating
A coating that reduces the glare from sideview mirrors by modifying the reflected light.
Post collision communication
A component of a vehicle's telemetrics system that, when triggered, automatically informs authorities after a collision.
Postcrash safety
Safety measures and devices that lessen the chance of a driver or passenger being hurt in the aftermath of a collision.
Power extending mirrors
An electronically controlled sideview mirror that can be moved further away from a vehicle when it is towing an object.
Precrash safety seats
Safety measures and devices that prevent a collision from occurring or lessen the chances of a driver or passenger injury in the event of a collision.
Precrash safety
Safety measures and devices that prevent a collision from happening or lessen the chances of a driver or passenger injury in the event of a collision.
Precrash system
A system of devices that employs radar or laser technology to sense an impending collision and reacts by implementing precautionary measures, including tightening seatbelts and applying braking.
Rear brake type
The type of rear brake: drum or disc.
Recall
A recall is a notice sent by a vehicle manufacturer to owners of a vehicle advising them that the vehicle has or may have a serious defect that may compromise the safety of the vehicle and that the service departments of that manufacturer's dealers will make any necessary replacements or repairs free of charge. 

Ordinarily, recalls affect only a portion of the production run of a given year, make and model. 

For more about recalls, please see A Quick Guide to Recalls. To find out about any recalls that may apply to your vehicle, please use our Maintenance Guide.
Recall notice
A notice by a manufacturer to the owners of a defective/unsafe vehicle or vehicle component (as well as dealers) that a recall has occurred.
Repair kit
Tire repair equipment that typically consists of an emergency tire sealant and a means of refilling a flat tire.
Retractable mirrors
Sideview mirrors that can be moved closer to a vehicle when parking in a tight space or using an automatic car wash.
Reverse tilt mirrors
Power sideview mirrors that tilt down when a vehicle is in reverse in order to aid the driver in parallel parking.
Roll-over protection
A system of devices that works to prevent or lessen the damage from rollover accidents.
Run flat
A tire that is capable of being driven on temporarily after losing its pneumatic pressure.
Seat belts
Harnesses designed to secure vehicle occupants during a collision.
Seatbelt force limiters
A part of the seatbelt pre-tensioner that helps prevent the seatbelt from being tightened to the point of injury to the occupant.
Seatbelt pretensioners
A seatbelt with a mechanism that reels in the belt when the airbag is deployed for the purpose of keeping the occupant in the proper position.
Self-leveling headlights
A system that uses suspension height sensors to determine the orientation of a vehicle's body for the purpose of making up-down adjustments to the direction of the headlights, for the protection of oncoming drivers.
Side airbags
Small airbags that deploy from the outside edge of a seat to protect the occupant's ribcage in a side impact collision.
Side curtain rollover sensor
A sensor that determines in the event of a collision whether or not it is necessary to deploy a vehicle's side curtain airbags.
Side impact beam
A structural support designed to protect a vehicle's occupants from side impacts.
Skid plate
A shield typically attached to the bottom of a vehicle's front bumper that is designed to guard the undercarriage in the case of insufficient ground clearance.
Spare
A fifth wheel and tire that is stored on or in a vehicle for use when one of the four tires in use becomes disabled.
Stability control
Also known as "electronic stability control," or "ESC." A safety feature that improves the safety of a vehicle's handling by detecting skids and compensating by adjusting braking pressure to help maintain the intended direction of the vehicle. Some stability control systems also reduce engine power until control is regained.
Tail lights
A set of housings that include a vehicle's brake lamps, reverse lights and rear turn signal lights.
TCS
See "Traction control."
Technical Service Bulletin
Technical service bulletins (TSBs) are issued by the manufacturer for problems that affect the normal operation of the vehicle. Sometimes called "secret warranties," TSBs cover known problems and provide repair instructions for service technicians and accordingly are distributed to all of the manufacturer's dealerships.

Unlike recall-related repairs, which are performed on a no-questions-asked basis, TSB repairs are made only to resolve problems that can be verified by dealer service technicians. And generally these repairs will be free of charge only if the vehicle is still under warranty. 

For more about TSBs, check out How Can a Technical Service Bulletin Help Me? and The Secret Warranty.

To find out about any TSBs that may apply to your vehicle, please use our Maintenance Guide.
Telemetrics
The integrated use of telecommunications and electronic data communications in a vehicle.
Tire pressure monitoring system
An electronic system that measures and displays to the driver the amount of pressure in a vehicle's tires.
Traction control
Also known as "traction control system," or "TCS." A safety feature that regulates wheel spin and prevents loss of control under acceleration by ensuring maximum traction and contact between the tires and the road (by adjusting brake pressure to one or more wheels, closing the throttle, or reducing the fuel supply to at least one or more cylinders).
Traction control system
See "Traction control."
Turn signals
Flashing amber-colored lights that indicate when a vehicle's driver intends to make a turn or lane change.
Understeer
A handling characteristic of a vehicle that causes it to turn less sharply than the driver intends because the front wheels are sliding to the outside of the turn.
 

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Specifications

A-pillar
See "Pillar."
Aerodynamic drag
For a moving vehicle, the force exerted by the flowfield of air moving in the opposite direction.
Angle of approach
The steepest angle of inclined roadway onto which a vehicle can be driven from a level roadway without the vehicle's forward overhang making contact with the inclined surface.
Angle of departure
The steepest angle of inclined roadway from which a vehicle can be driven onto a level roadway without the vehicle's rear overhang making contact with the inclined surface.
Axle ratio
The number of revolutions a vehicle's driveshaft makes for each revolution of the vehicle's drive axle(s).
B-pillar
See "Pillar."
Bed dimensions
The physical dimensions of a truck's bed, consisting of width, height and depth.
Bed length measurement
The inside length of a pickup truck's cargo box or "bed," measured from the front wall to the face of the closed tailgate.
Beltline
The horizontal line defined by the lower edges of a vehicle's windscreen, rear and side windows and pillars.
Bore
The diameter, in inches, of the cylinders in the vehicle's engine.
Breakover angle
The maximum angle at which a vehicle can traverse a sharp ridge without making contact or hanging up between axles.
C-pillar
See "Pillar."
Compression ratio
The ratio of (i) the volume of a vehicle's engine cylinder with its piston at bottom dead center to (ii) the volume of the same cylinder with its piston at top dead center.
Curb weight
The total weight of a vehicle, including a full tank of fuel, all fluids and standard equipment, but without any cargo or passengers.
Displacement (CC's)
The volume, in cubic centimeters, of a vehicle's engine cylinder with its piston at bottom dead center, multiplied by the total number of cylinders in the vehicle's engine.
Electric motor performance
An electric vehicle's or hybrid vehicle's electric motor's ability to do work, expressed in terms of horsepower, torque or kilowatts.
Engine size
A vehicle engine's displacement, in liters (according to its manufacturer).
EPA interior volume
The amount of total space within the cabin of a vehicle as measured by the EPA.
Front brakes specifications
The dimensions of the major components of a vehicle's front brake rotors, and the type of brake ventilation employed.
Fuel capacity
The amount of fuel that a vehicle's fuel tank can hold.
Greenhouse
The portion of a vehicle above its beltline.
Gross vehicle weight rating
Also referred to as "GVWR." The sum of a vehicle's curb weight, cargo weight capacity and passenger weight capacity.
Ground clearance
The distance between the lowest point of a vehicle and level ground.
GVWR
See "Gross vehicle weight rating."
Head room
The distance from the hip of a vehicle's occupant to the vehicle's interior rooftop.
Height
The distance between the tallest part of a vehicle and level ground.
Hip room
The distance from the driver's side lower door panel to the front passenger's lower side door panel.
Hybrid gas engine performance
A hybrid vehicle's gasoline engine's ability to do work, expressed in terms of horsepower or torque.
Leg room
The distance from the floor of a vehicle (a person's ankle point) to the centerline of the seat (a person's hip joint).
Length
The distance from the most forward-facing point of a vehicle to the most rearward point.
Load height
The minimum height to which an item must be lifted in order to be loaded into a vehicle's cargo area.
Load rating
See "Tire load index."
Luggage capacity
A measurement of a vehicle's trunk/cargo volume with all standard seats in place.
Maximum cargo capacity
A measurement of a vehicle's cargo volume when the rear seats (including a third row if applicable) are folded or removed.
Passenger volume
The total volume of space available for passengers in the front and rear seat(s) of a vehicle.
Payload
A vehicle's carrying capacity (in pounds) of occupants and cargo, and equal to the vehicle's Gross Vehicle Weight Rating (GVWR) minus its curb weight.
Pillar
A shaft or other structure that supports the roof of a vehicle, with the A-pillars being the structures that frame the windscreen, and each successive set of structures (moving toward the rear of the vehicle) being named after successive letters of the alphabet.
Rear electric motor performance
An electric vehicle's or hybrid vehicle's rear electric motor's ability to do work, expressed in terms of horsepower, torque and/or kilowatts.
Roofline
The outline or contour of the roof a vehicle.
Shoulder room
The distance from the driver's upper door panel to the front passenger's upper door panel.
Stroke
The distance, in inches, between the centerline of an engine's crankshaft and the centerline of its connecting rod journal.
Suspension geometry
The relationship between the placement of the mounting points for each of a vehicle's suspension components.
Tire diameter
The diameter, in inches, of a tire.
Tire load index
Also referred to as "load rating." A numerical value assigned to a tire by its manufacturer to indicate the tire's capability to carry a load The higher the index number, the greater its load capability.
Tire prefix
An alphabetic value assigned to a tire by its manufacturer to indicate intended uses, such as "P" for passenger cars and "LT" for light trucks.
Tire profile
A numeric value assigned to a tire by its manufacturer to indicate the relationship between the tire's sidewall height and its tread width.
Tire size
Information displayed on the sidewall of a tire that includes its prefix and information about its dimensions, load capacity and speed rating.
Tire speed rating
An alphanumeric value assigned to a tire by its manufacturer that indicates the maximum speed the tire can safely sustain for a ten-minute period.
Towing capacity
The maximum amount of weight a vehicle is capable of towing (according to its manufacturer).
Track
The distance from the center plane of one wheel to the center plane of its opposing wheel.
Turning circle
Also referred to as "turning diameter." The diameter of the circle made by a vehicle in a full-lock 360 degree turn.
Wheel diameter
The diameter, in inches, of a vehicle's wheel.
Wheel offset
The distance from a wheel's hub-mounting surface to the centerline of the wheel. Zero offset means the hub-mount surface is even with centerline. Positive offset means the hub-mount surface is towards the front (or outside) of the centerline. Negative offset means the hub-mount surface is towards the back (behind) of the centerline.
Wheel specs
The dimensions of a vehicle's wheels.
Wheel width
The distance of a wheel from bead to bead.
Wheelbase
The distance between the center of a vehicle's front axle and the center of its rear axle.
Width
The width of a vehicle at its widest point.
 

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Vehicle Classification

Automated manual transmission
Also referred to as "DSG," "direct shift gearbox," "SMG" and "sequential manual gearbox." A conventional clutch-type manual transmission that employs electronic, pneumatic and/or hydraulic actuators in place of a conventional clutch pedal, and a purely mechanical shift lever. The driver may select either fully automatic shift mode or driver-controlled shift mode.
Automatic transmission
A transmission that uses a torque converter, planetary gearset and clutches or bands to automatically change a vehicle's gears.
AWD
All-wheel drive. A drivetrain that employs a front, rear and center differential to provide power to all four wheels of a vehicle.
Cargo door type
The type of cargo door: liftgate, vertical split-hinge or horizontal split-hinge.
Cargo hauler
A vehicle that is well-adapted for hauling cargo.
CVT
A transmission with a continuously variable drive ratio (as opposed to conventionally stepped gear ratios) that maintains a steady acceleration curve with no pauses for gear changes.
Cylinder configuration
The arrangement of an engine's cylinders.
Diesel engine
A vehicle with an engine that uses diesel fuel and compression ignition.
Direct shift gearbox
Also referred to as "DSG," "SMG," "sequential manual gearbox" and "automated manual transmission." See "Automated Manual Transmission."
Drive system
The type of drive system: two-wheel drive, four-wheel drive or all-wheel drive
DSG
Direct shift gearbox. Also referred to as "SMG," "sequential manual gearbox" and "automated manual transmission." See "Automated Manual Transmission."
Electric vehicle
A vehicle that is run entirely on electricity, using batteries, capacitors and one or more traction drive systems.
Factory tuner
A "Factory Tuner" is a vehicle model that has significant engine and/or chassis upgrades as compared its parent model. It is built at the factory and typically has a name that includes a "factory tuner" designation (e.g. Mercedes-Benz "AMG" or BMW "M"). Examples include the BMW M3 and the Cadillac XLR-V.
FF
Front-engine front-wheel drive. A vehicle that is propelled solely by its front wheels and whose engine is located forward of its front axle.
Flex-fuel engine
An engine that can be run on more than one type of fuel (for example, E85 and gasoline).
4WD
A drivetrain that employs two differentials and a transfer case to provide power to all four wheels of a vehicle.
FR
Front-engine rear-wheel drive. A vehicle that is propelled solely by its rear wheels and whose engine is located forward of its front axle.
Front mid engine
A vehicle with an engine that is forward of its passenger compartment but aft of its front axle.
Fuel cell vehicle
A vehicle that utilizes fuel cells to create electricity through a chemical process using oxygen from the air and hydrogen.
Gas/electric hybrid engine
A powertrain that combines an electric motor and a gasoline or diesel internal combustion engine.
Gasoline engine
An internal combustion engine that burns conventional gasoline.
HCCI
Homogeneous charge compression ignition. An internal combustion engine in which gasoline and air are compressed to the point of auto-ignition.
Hinge type
The type of door hinge: standard, scissor, gullwing or suicide-style.
Hybrid engine
A powertrain that combines an electric motor and an alternative means of propulsion and/or power generation (for example, hydrogen). A gas/electric hybrid engine is the most common example of a hybrid engine.
Limited production vehicle
A vehicle for which the manufacturer has established a limit on the number units to be produced, without regard to the maximum number the manufacturer may be able to sell. These vehicles typically have special interior and/or exterior trim and/or costly performance enhancements that distinguish them from their mainstream counterparts.
Make
For a vehicle, either the name of its manufacturer or, if the manufacturer has more than one operating unit, the name of that unit.
Manual transmission
A transmission that uses a clutch and a shift (gear) selector to change gears.
Manufacturer's engine code
An alphanumeric code given to an engine by its manufacturer in order to distinguish it from other engines.
Mid-engine
A vehicle that is propelled solely by its rear wheels and whose engine that is aft of the passenger compartment but forward of the rear axle.
Model
A specific vehicle brand identified by a name or number (and which is usually further classified by trim or style level).
Model year
For a vehicle model, the calendar year designation assigned by the manufacturer to the annual version of that model.
Natural gas engine
An internal combustion engine that burns natural gas.
Off-road ready
A vehicle with high-ground-clearance outfitted for the rigors of traveling on non-paved roads.
Rear door type
The type of rear door: hinged or sliding.
Recommended fuel type
The optimal type of fuel (based on its octane rating) recommended by a vehicle's manufacturer.
Required fuel type
The minimum acceptable type of fuel (based on its octane rating) recommended by a vehicle's manufacturer.
RR
Rear-engine rear-wheel drive. A vehicle that is propelled solely by its rear wheels and whose engine is located aft of its front axle.
Sequential manual gearbox
Also referred to as "SMG," "direct shift gearbox," "DSG" and "automated manual transmission." See "Automated Manual Transmission."
Shift control mechanism
The location of the shift control mechanism, which includes levers, paddles or buttons.
Shiftable automatic transmission
An automatic torque converter transmission equipped with a feature that permits the driver to actively select either fully automatic or driver-controlled shift modes by using a dual-gate shifter and/or remote shifter controls.
SMG
Sequential manual gearbox. Also referred to as "DSG," "direct shift gearbox" and "automated manual transmission." See "Automated Manual Transmission."
Targa
A semi-convertible body style with a removable roof section and a full-width roll bar behind the seats.
Towing capable
A vehicle with features and equipment that make it well-suited for pulling a trailer.
T-top
A vehicle roof with removable panels on either side of a rigid bar, running from the center of the vehicle's A pillar to the center of its B pillar.
Valve gear type
The number of camshafts used by an engine, as well as their orientation in relation to its valves.
Vehicle type
The type of vehicle class, examples of which are large cars, midsize cars, minivans, pickup trucks, small cars, special purpose vehicles, sports utility vehicles, station wagons and vans.
 

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Warranty

Basic/Bumper to bumper warranty
A vehicle warranty that covers everything except items that are subject to wear and tear or replacement in the ordinary course of vehicle ownership, such as oil and air filters, wiper blades and brake pads. Tires and batteries are often excluded, but usually have their own warranty provided by the manufacturers of those items. Emissions equipment is required by Federal law to be covered for two years or 24,000 miles.
Drivetrain warranty
See "Powertrain warranty."
Extended warranty
A vehicle warranty sold by the manufacturer of the vehicle or a third party that extends the vehicle's basic warranty beyond its original period.
Limited warranty
A vehicle warranty that is in effect for a specified number of years and/or miles driven.
Powertrain warranty
Also referred to as the "drivetrain warranty." A vehicle warranty that covers most of the parts that make the vehicle move, including the engine, transmission, drive axles and driveshaft. As with a basic warranty, "consumable" parts such as hoses and belts are not covered. However, most of the internal parts of the engine, such as the pistons and bearings, which are also subject to wear and tear, are covered by a powertrain warranty.
Roadside assistance
A service available from various manufacturers that assists a driver when a vehicle is inoperable.
Rust & corrosion warranty
A warranty that covers the repair or replacement of the vehicle's sheet metal in the event of damage from rust or corrosion that is severe enough to cause a hole. Surface rust is not covered.
Scheduled maintenance warranty
A warranty that covers service procedures recommended by the manufacturer at predetermined intervals to preserve and/or prolong the life of a vehicle.
 

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