P0476: exhaust throttle position-tracking performance

The P0476 monitor compares the exhaust throttle valve's requested position with measured position. An absolute tracking error above 10% is the documented failure criterion in this GM strategy.

A longer filtered performance assessment

The table requires 1,700 failed counts among 2,125 samples on a 6.25 ms task. It also enables the P0475 open-circuit check at 480 failed counts. That relationship can reveal an electrical explanation for movement that initially appears obstructed.

The continuation requires a setpoint rate between −100 and 100% per second for at least 0.50 second. Closed-loop control must be active, and mechanical-stop soft approach and anti-sticking procedures must be inactive. A rapidly changing request is therefore poor evidence for judging this particular monitor.

Verify an eligible command

Other gates include no cranking, relay supply above 11 V, cold-start strategy inactive, valid temperature inputs, outside air at least −20°C and coolant at least 40°C or the cooling-system target reached.

Confirmation should show measured position following a stable request with valid feedback and no relevant electrical fault. The code does not directly report an exhaust pressure value or prove that deposits caused the mismatch. Use the correct service procedure to distinguish actuator loading, position feedback and mechanical response before choosing a repair; the summary provides no disassembly instructions.

Source and applicability

2025 GM 25OBDG04B diagnostic parameter tables; the cited monitor only. Vehicle, engine and calibration applicability must be confirmed separately. These tables describe detection logic, not a complete repair procedure or a component replacement verdict. gm-2025-04b, PDF page 1196; gm-2025-04b, PDF page 1197.