P0108: Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

What does the P0108 error code mean?

The P0108 diagnostic trouble code stands for "Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage." The MAP sensor measures the absolute pressure inside the air intake manifold and sends the information to the powertrain control module, which uses that info to calculate the correct air-fuel mixture for efficient engine operation. A P0108 code is thrown when the voltage measured by the MAP sensor is higher than expected, which can be caused by the sensor, its associated wiring, or, more rarely, an issue with the manifold.

Why is this issue important?

The powertrain control module relies on the MAP to provide an accurate reading of the air pressure entering the intake manifold so it knows how much fuel is needed to maintain a proper air-fuel mixture. An inaccurate air pressure reading can lead the powertrain control module to misjudge the amount of fuel that is needed, resulting in problems like increased fuel consumption and the engine failing to start at all.

Can I safely drive my car with this error code?

We do not recommend driving a car with this error code present. It's possible that the sensor itself is faulty or the wiring powering the sensor or supplying information to the powertrain control module is damaged. In these cases, symptoms can include increased fuel consumption, a rough idle, or an engine that fails to start or stalls at idle. While these don't seem like serious issues, they can cause permanent damage to an engine. It's also entirely possible that the sensor is performing the way it's supposed to, and the abnormal voltage readings it's noting are because of a vacuum leak or a different component not functioning properly. These, too, are serious concerns that should be addressed by a qualified technician before starting the car again. 

Common symptoms of the P0108 error code

• Illuminated check engine light
• Poor acceleration
• Rough idling or stalling
• Increased fuel consumption
• Black exhaust smoke
• Failure to start the engine

How is the P0108 error code diagnosed?

Diagnosing the P0108 error code begins by plugging in an OBD-II scanner and verifying the presence of this error code. While repairs should be performed by a qualified mechanic, there are a few things you can do to identify a possible cause for the error code before you bring it into a shop:

• Check for any related codes: As stated above, it's possible that the MAP sensor is functioning properly and a different component is causing the problem. Look for stored error codes related to the intake and emissions control systems.
• Inspect the MAP sensor and wiring: Look for loose connections, damaged wiring or corrosion.
• Test the MAP sensor voltage: Use a multimeter to check the sensor’s output voltage under various throttle loads to determine if the voltage is atypical. It should read around 1 volt when the system is idling and about 5 volts at wide-open throttle.
• Check the intake hoses: Inspect the intake hoses to identify obvious leaks that could reduce air pressure in the manifold.

How is the P0108 error code repaired?

• Secure connections on the MAP sensor's circuit.
• Replace the MAP sensor's damaged wiring or connectors.
• Replace the faulty MAP sensor.
• Inspect and fix any vacuum leaks in the intake manifold or hoses.
• Reset the error code and perform a test drive to ensure the issue is resolved

Related reading

Follow the link below to reach our diagnostic check engine trouble codes catalog:
On-board diagnostics (OBD-II) trouble code directory