P0171 AND P0174 Inspect For Cracked Or Leaking PCV Pipe - keywords alcohol cover crack DTC fuel hose idle injector intake leak lean long MIL misfire 4.8 5.3 6.0 6.2 L76 L92 LC9 LH6 LR4 LY2 LY5 LY6
| Subject: | P0171 and P0174 Inspect For Cracked or Leaking PCV Pipe |
| Models: | 2007 Cadillac Escalade |
| 2007 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe, Trailblazer |
| 2007 GMC Envoy, Savana, Sierra, Yukon |
This PI was superseded to update models and engines. Please discard PIP3918.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A vehicle may be brought to the dealer for a rough idle and a SES light on. DTCs P0171 and P0174 may also be found.
Recommendation/Instructions:
Complete the current SI diagnostics for any symptoms or trouble codes found. During diagnosis inspect for a leaking or cracked PCV pipe. The PCV pipe is covered with insulation, and the covering could make it difficult to hear a vacuum leak.
Repair or replace the PCV pipe as needed.
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.
