P25B5: Reading bank-two wastegate stuck-open without reversing the scale

For P25B5, GM’s documented controller assigns an open-side jam to the bank-two wastegate after prolonged position-control disagreement. The enable logic includes a governor deviation beyond ±40% and a period longer than one second. A short mismatch during motion does not automatically satisfy that pattern.

Check what zero percent means

The table explicitly branches on the status that defines zero-percent as closed. If that status is false, position below 50% belongs to the open classification; if true, position above 50% does. A generic scan display that omits the convention cannot safely establish which physical direction the percentage represents.

Preserve the monitor window

The bank-two actuator must be active. Initial end-stop learning and an actuator test must be inactive, with valid disturbance-pressure information and no power-stage disable condition. These prerequisites should accompany any claim that a follow-up event reproduced or cleared the fault.

The useful investigation is whether requested movement, position response and the configured scale agree under those conditions. A stuck-open label alone does not prove a seized valve, failed motor or erroneous feedback. The cited summary supplies the classification logic, leaving the vehicle-specific isolation procedure to applicable service documentation.

Document scope and source

2025 GM 25OBDG07A Part 2 documented monitor only; its application-matrix filename join is unresolved. No model, engine or universal calibration applicability is inferred. These figures explain the cited controller logic, not a vehicle-specific repair instruction. Match the vehicle’s service information before applying them.

GM physical PDF page 867, GM physical PDF page 868.