Circuit/System Verification

Verify that the stop lamps operate properly and that no B22 Brake Pedal Position Sensor related DTCs are set.
- If brake pedal position sensor related DTCs are set
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle
- If no brake pedal position sensor related DTCs are set
Verify that no DTCs are set, except DTC P0571.
- If any other DTC is set, except DTC P0571
  Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- If only DTC P0571 is set
Replace the K20 Engine Control Module.
Verify DTC P0571 does not set when operating the vehicle within the conditions for running the DTC.
- If the DTC sets
  Replace the K9 Body Control Module.
- If the DTC does not set
All OK.