DTC P0171, P0174: Notes
DTC P0171, P0174 (MZI-3.5) DETECTION CONDITION AND POSSIBLE CAUSES
| DTC P0171 |
P0171: System too lean (RH) |
| DTC P0174 |
P0174: System too lean (LH) |
| DETECTION CONDITION |
- P0171 indicates that the fuel/air ratio is too lean (RH).
- P0174 indicates that the fuel/air ratio is too lean (LH).
- The adaptive fuel strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit.
|
| POSSIBLE CAUSE |
Fuel System:
- Damaged or leaking fuel pulse damper
- Fuel filter plugged or dirty
- Damaged or worn fuel pump
- Leaking fuel pump check valve
- Leaking/contaminated fuel injectors
- Low fuel pressure or running out of fuel
- Purge solenoid valve is leaking when the canister is clean
- Fuel supply line restricted
- Fuel rail pressure sensor bias
Exhaust System:
- Exhaust leaks in the exhaust manifold gasket or mating gaskets before or near the HO2S
Intake Air System:
- Air leaks after the MAF sensor
- Vacuum leaks
- PCV system is leaking or the valve is stuck open
- Improperly seated engine oil dipstick
- Damaged or contaminated MAF sensor
|