P0174: System Too Lean (Bank 2)

The P0174 error code tells you that the vehicle's engine control module (ECM) has detected that the fuel-to-air ratio on bank No. 2 of the engine is too lean. (Bank No. 2 is the side of the engine that does not house the first cylinder.) That means there's too much air and not enough fuel, and this can cause engine misfires and increased combustion temperatures and might even lead to damage of vital components like the valves and pistons.

Is it safe to drive my car with the P0174 error code?

No — at least not for a prolonged period. Because an improper air-to-fuel ratio can cause damage to your engine components, the longer you drive with this issue unresolved, the more likely it is that you'll encounter serious problems (and costly repairs).

Common symptoms of the P0174 error code

• Your vehicle's check engine light is illuminated
• The engine is misfiring or not starting properly
• The engine's idle is rough
• Power and acceleration reduced, or the vehicle hesitates or stalls
• You might notice reduced fuel economy

How to diagnose the P0174 error code

Like all vehicle error codes, the P0174 code is found via an OBD-II scanner, and a mechanic will make a visual inspection of components like vacuum hoses and the vehicle's intake system. A mechanic will also check the vehicle's fuel system and oxygen sensor, as well as the mass air flow sensor, to ensure it's measuring the correct amount of air entering the engine.

How to repair the P0174 error code

Fixing the P0174 error code issue typically involves one or more of the following steps:

• Replace or repair any vacuum leaks.
• Replace or clean the mass air flow sensor.
• Replace or clean the fuel injectors.
• Replace any faulty oxygen sensors.
• Update or reprogram the engine control module.
• Finally, the mechanic can clear the engine's error code.

Related reading

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