GM Service Manual Online
For 1990-2009 cars only

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

  1. Perform the Diagnostic System Check - Vehicle before using the symptom tables in order to verify that all of the following are true:
  2. • There are no DTCs set.
    • The control modules can communicate via the serial data links.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to:
  4. •  Electronic Park Lock Description and Operation
    •  Power Mode Description and Operation
    •  Retained Accessory Power Description and Operation

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the 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

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:

    •  Ignition Can/Cannot Be Turned Off with Transmission in Any Gear
    •  Power Mode Mismatch
    •  Retained Accessory Power Malfunction