GM Service Manual Online
For 1990-2009 cars only

The following steps must be completed before using the symptom diagnostic procedures:

    • Perform the Diagnostic System Check - Vehicle before using the symptom diagnostic procedures in order to verify that all of the following are true:
       - There are no DTCs set.
       - The control modules can communicate via the serial data link.
    • Review the system descriptions and operations in order to familiarize yourself with the system functions. Refer to one of the following system operations:
       -  Battery Description and Operation
       -  Charging System Description and Operation
       -  Electrical Power Management Description and Operation

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the starting and charging systems. Refer to Checking Aftermarket Accessories.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

    •  Battery Inspection/Test
    •  Battery Charging
    •  Battery Electrical Drain/Parasitic Load Test
    •  Charging System Test