P0171 Code: Meaning, Causes, and Symptoms | OBD2 Codes
P0171 – System Too Lean Bank 1
P0171: DIY Repairing Video Tutorial
Check out nonda Auto DIY Center for more engine error code repairing videos.
https://www.youtube.com/playlist?list=PL-Lyko0O0oxHe1AGvzwAz-wokJPXAtW97
P0171 Possible Causes
Intake air leaks
Faulty front heated oxygen sensor
Ignition misfiring
Faulty fuel injectors
Exhaust gas leaks
Incorrect fuel pressure
Lack of fuel
Faulty Mass Air Flow (MAF) sensor
Incorrect Positive Crankcase Ventilation (PCV) hose connection
P0171: DIY Repairing Video Tutorial
Check out nonda Auto DIY Center for more engine error code repairing videos.
https://www.youtube.com/playlist?list=PL-Lyko0O0oxHe1AGvzwAz-wokJPXAtW97
P0171 Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
Excessive Fuel Consumption
Description
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios. In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the Malfunction Indicator Light (MIL) (2 trip detection logic).