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Tahoe / Yukon Service Manual

Symptoms - Immobilizer

  1. Perform the Diagnostic System Check - Vehicle before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data links.
  2. Review the system operation in order to familiarize yourself with the system functions. Refer to Immobilizer Description and Operation. Visual/Physical Inspection Inspect for aftermarket devices which could affect the operation of the systems. 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 OnStar Stolen Vehicle Slowdown Active to diagnose the symptom.