Pinpoint Test N: Park Does Not Engage
- Normal Operation and Fault Conditions
- Gear Shift Module (GSM)
- If any diagnostic trouble codes (DTCs) are present in the GSM, resolve those first.
- Using a diagnostic scan tool, access the GSM and monitor PID GEAR_CMD. Press all the GSM buttons in sequence and make sure PID GEAR_CMD matches each selector lever position. If PID GEAR_CMD does not change to match the selected button, INSTALL a new GSM. REFER to: Gear Shift Module (GSM) .
- Park is manually released
- Verify park is not manually released. REFER to: Transmission Park by Wire Manual Release .
- Internal transmission components
- Check the park lock pawl solenoid operation. For 8F35 transmissions, REFER to: Main Control Valve Body . For 8F57 transmissions, REFER to: Main Control Valve Body .
- Check the park pawl and actuator rod for damage. For 8F35 transmissions, REFER to: Transmission . For 8F57 transmissions, REFER to: Transmission .
Possible Sources
- GSM fault
- Park is manually released
- Internal transmission park components
- Gear Shift Module (GSM)
Diagnostic steps are not provided for this symptom or DTC. REFER to: Diagnostic Methods .