GM Service Manual Online
For 1990-2009 cars only

Important: 

  1. Perform the Diagnostic System Check before using the Symptom Tables in order to verify that all of the following are true:
  2.    • There are no DTCs set.
       • The control module(s) can communicate via the serial data link.
  3. Review the system operation in order to familiarize yourself with the system functions. Refer to .

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the RTD System. Refer to Checking Aftermarket Accessories in Wiring Systems.
    • Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
    • Inspect the connectors to be properly seated and free of corrosion.
    • Inspect air lines for kinks and leaks.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Symptom List

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

    •  SERVICE RIDE CONTROL Message Inoperative
    •  SERVICE RIDE CONTROL Message Always On
    •  Automatic Level Control Compressor Motor Always On
    •  Automatic Level Control Compressor Motor Inoperative