Troubleshoot the immobilizer system by the order of the priority shown:

Order of Priority	Symptom	Possible cause
1	Immobilizer indicator blinks after the ignition switch turned OFF.	Symptom troubleshooting.
2	Engine does not start with the immobilizer key.	Symptom troubleshooting.
3	Immobilizer indicator does not come on.	Check the MIL indication. If the MIL comes on, go to the Fuel and Emissions system MIL circuit troubleshooting. If the MIL does not come on, go to the gauge control module (tach) self-diagnostic function.
4	Immobilizer indicator does not go off.	Symptom troubleshooting.