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 there are no DTCs set.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to Theft Systems Description and Operation .

Visual/Physical Inspection

    •  Inspect for aftermarket devices which could affect the operation of the Theft Deterrent System. Refer to Checking Aftermarket Accessories .
    •  Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
    • Inspect that the transmitter is the correct model for the vehicle. An incorrect model will not operate the Theft Deterrent System.

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 the following list in order to diagnose the symptom:

    •  Communication Between Immobilizer Control Unit and Test Equipment
    •  Content Theft Deterrent (CTD) Alarm Mode Always On
    •  Content Theft Deterrent (CTD) Alarm Mode Inoperative
    •  Content Theft Deterrent (CTD) Does Not Disarm with Key Lock
    •  Key Status Errors
    •  Lights Inoperative in Content Theft Deterrent (CTD) Alarm Mode
    •  Security Indicator Always On or Flashing
    •  Security Indicator Inoperative
    •  Theft Deterrent Alarm Inoperative