For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: The VOLT indicator or the CHECK GAGES message with engine outline telltale stays on when the engine is running.
1 | Monitor the system voltage using scan tool while the engine is running. Is the system voltage above the specified value? | More than 10.6 V | Go to Step 2 | Go to Step 3
2 | Place the ignition in PARK. Disconnect the PCM C2. Turn ON the ignition. Is the indicator still on? | -- | Go to Step 4 | Go to Step 5
3 | Inspect the generator. Repair as needed. Are the repairs complete? | -- | System OK | --
4 | Inspect the BRN 25 wiring for a short to ground. Refer to Section 8A. Repair as needed. Are the repairs complete? | -- | System OK | --
5 | Inspect the PCM C2 contact. If OK, refer to Engine Controls for PCM System Check. Repair or replace as needed. Are the repairs complete? | -- | System OK | --

Olsdmibile vehicles with gauge cluster UH8 or U2A receive change light input via Uart Dataline. Refer to Electronic Diagnosis.