P2C9C: Second wastegate channel fails the CSERS tracking check

P2C9C is the bank 2 wastegate tracking diagnosis during CSERS, the documented cold-start emissions-reduction strategy. The source includes both stuck-open and stuck-closed branches. A reader needs the underlying branch or enhanced status to know which behaviour was observed.

The percentage is not self-explanatory

The monitor changes its comparison according to whether zero-percent position means closed. It combines that convention with a fifty-percent position boundary and a governor-deviation fault outside plus or minus forty percent. Timing qualifications exceed one second.

This makes the configured interpretation of position essential. Comparing bank 2's displayed percentage with a general expectation about “open” and “closed” can reverse the intended meaning. Preserve the convention, command and jammed-state result together whenever the diagnostic equipment provides them.

Eligibility limits the conclusion

The source requires CSERS operation and an active actuator, with valid supporting states. It excludes the actuator test, first end-stop learning and power-stage disabling conditions. A warm-engine test performed outside that strategy can show movement without proving that the original monitor passed.

Several enable fields are imperfectly documented, including a greater-than-TRUE offset-learning expression and awkwardly aligned continuation text. These are not repaired by inventing a universal test sequence. Use the exact service routine to resolve the operating conditions and examine the actuator safely. The code describes a tracking judgement under a particular strategy; it does not identify a replacement assembly or justify forcing the linkage by hand.

Source and applicability

2025 GM 07A-2 documented monitor only; module and calibration applicability must be matched to the vehicle. The application-matrix filename join remains unresolved; no model or engine fitment is inferred. GM PDF, page 870. GM PDF, page 871. GM PDF, page 872.