PCM sets DTC P0171 when short term trim value at Max. limit for more than 40 sec. of total monitoring time(90 sec.).
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Monitoring the deviation of short term fuel trim | 1. Poor Connector Connection 2. Air leakage or restriction in Intake or Exhaust System 3. Dirty Engine Oil or Oil Level Too High 4. Defected Upstream O2 Sensor 5. Defected MAP Sensor 6. Defected Fuel System 7. Defected EVAP System 8. Faulty Sensor Signals |
Enable Conditions |
•
Engine Coolant Temp. higher than 163.4℉(73℃)
•
Lambda Control Active :
–
No relevant failure(Upstream O2 Sensor, Injector Valve, ETC in Limp home state)
–
Measured Tip Temp. higher than 1184℉(640℃)
–
Engine Coolant Temp. Higher than 32℉(0℃)
•
No relevant DTC present | |
Threshold Value |
•
Short term trim more than or equal to 50% | |
Diagnostic Time |
•
90 sec. | |
Mil On Condition |
•
2 Driving Cycle |
