GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    •  Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Reference Information

Description and Operation

Charging System Description and Operation

Electrical Information Reference

Testing for Intermittent Conditions and Poor Connections

Circuit/System Verification

Engine ON, observe the charge indicator on the instrument panel cluster (IPC) or message in the driver information center (DIC). The charge indicator on the IPC should be turned OFF and the DIC should not display charging system message.

If the charge indicator is not on the IPC or a charging system message is not displayed on the DIC, refer to Testing for Intermittent Conditions and Poor Connections .
If the charge indicator is on the IPC or a charging system message is displayed on the DIC, refer to Circuit/System Testing.

Circuit/System Testing

  1. Ignition ON, verify that no generator or battery current sensor DTCs are set that would cause a charging system concern.
  2. If DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .
  3. Engine OFF, connect the SA9154Z-A Starting System Tester red lead to the battery positive terminal and the grey lead to the output circuit of the generator.
  4. Engine ON, turn ON the SA9154Z-A Starting System Tester. Turn all vehicle accessories OFF and follow all the prompts.
  5. Press the CHARGING SYSTEM TEST button. The display should read 13.0 - 15.5 volts.
  6. If not within specified range, replace the generator.
  7. Is the generator output current greater than or equal to the load test output value given in Generator Usage ?
  8. If not within specified value, replace the generator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Generator Replacement