GM Service Manual Online
For 1990-2009 cars only

The following steps must be completed before using the symptom tables.

    • Perform Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:
       - The power modes are correct.
       - The control modules can communicate via the serial data link.
       - There are no DTCs set.
    • 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
       -  Starting System Description and Operation

Visual/Physical Inspection

    • Inspect the high voltage system. Refer to High Voltage System Inspection.
    • Inspect for aftermarket devices which could affect the operation of the 12 V charging system. Refer to Checking Aftermarket Accessories.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

Faulty 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
    •  Battery Common Causes of Malfunction
    •  Charging System Test