GM Service Manual Online
For 1990-2009 cars only

Important: 

  1. Before using the symptom diagnostic tables, perform the Diagnostic System Check - Vehicle in order to verify the following conditions:
  2.    • There are not any DTCs set.
       • The control modules can communicate via the serial data link.
  3. Review the system operation in order to understand the system functions. Refer to Cruise Control Description and Operation .

Visual/Physical Inspection

    • Inspect for aftermarket devices which could affect the operation of the cruise control system. Refer to Checking Aftermarket Accessories .
    • Inspect the easily accessible or visible system components for obvious damage or for 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 Cruise Control Inoperative/Malfunctioning in order to diagnose the symptom.