SES Light Due to a P0171 DTC - Check Purge Valve Operation - keywords CEL check ECM lamo lean light PCM repeat trim updated
| Subject: | SES Light Due to a P0171 DTC - Check Purge Valve Operation |
| Models: | 2006 Pontiac Vibe |
| with Automatic Transmission (RPO MU4) |
| and Base Front Wheel Drive (5th Digit of VIN = L) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
On rare occasions, a check engine light may be experienced due to a P0171 DTC. This may be the result of an EVAP purge solenoid driver staying on inside of the PCM, which will keep the purge solenoid fully open.
Recommendation/Instructions:
If the SI diagnostics do not isolate a cause for the concern, check EVAP purge solenoid operation with a Tech 2. If normal purge solenoid operation is noted, review PIP3643, which relates to a potential O2 sensor concern.
If the purge solenoid is stuck open when it is commanded off with the Tech 2 but it closes normally when it is unplugged, inspect the EVAP purge solenoid control circuit for a short to ground. If there is no problem found with the EVAP purge solenoid control circuit, replace the PCM.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
