Antitheft and Alarm Systems: Testing and Inspection
Immobilizer SystemTroubleshooting
Before troubleshooting the immobilizer system, troubleshoot any PCM diagnostic trouble codes (DTCs), and make sure the PCM has no malfunction.
Note these items before troubleshooting:
- Due to the action of the immobilizer system, the engine takes slightly more time to start than a vehicle without an immobilizer system.
- When the system is normal, and the proper key is inserted, the indicator light comes on for 2 seconds, then it will go off.
- If the indicator starts to blink after 2 seconds. on the engine does not start, remove any other immobilizer keys or large key fobs on the key ring then repeat the starting procedure.
If the engine still does not start, continue with this procedure.
1. Turn the ignition switch ON (II) with programmed key.
2. Check to see if the immobilizer indicator light comes on.
Does the indicator light come on for 2 seconds?
YES - Go to step 10.
NO - Go to step 3.
3. Try to start the engine.
Does the engine start?
YES - Go to step 4.
NO - Go to step 9.
4. Remove the dashboard lower cover.
5. Remove the steering column lower cover.
6. Disconnect the 7P connector (A) from the immobilizer control unit receiver (B).
7. Check for voltage between the immobilizer control unit-receiver 7P connector No.7 terminal and body ground.
Is there battery voltage?
YES - Go to step 8.
NO - Check for these problems.
- Blown No.13 (7.5 A) fuse in the passenger's under-dash fuse/relay box.
- An open in the WHT/YEL wire.
8. Check for continuity between the immobilizer control unit-receiver 7P connector No.5 terminal and gauge assembly B9 terminal.
Is there continuity?
YES - Faulty immobilizer indicator light.
NO - An open in the wire.
9. Check for voltage between the immobilizer control unit-receiver 7P connector No.6 terminal and body ground with the ignition switch ON (II).
Is there battery voltage?
YES - Poor ground G101.
NO - Check for these problems:
- Blown No.6 (15A) fuse in the driver's under-dash fuse/relay box.
- Blown No.92 (7.5A) fuse in the auxiliary fuse holder 3.
- An open in the BLK/YEL wire.
- An open in the GRN/WHT wire.
10. Check to see if the immobilizer indicator light comes on.
Does the indicator light come on for 2 seconds, then go off?
YES - Go to step 11.
NO - Go to step 13.
11. Try to start the engine.
Does the starter motor operate?
YES - Go to step 12.
NO - Check the starter motor.
12. Try to start the engine.
Does the engine start?
YES - Operation is normal.
NO - Check the PCM.
13. Check to see if the immobilizer indicator light comes on and blinks.
Does the indicator light blink?
YES - Go to step 14.
NO - Using the HDS, check the immobilizer control unit-receiver.
14. Try to start the engine.
Does the engine start?
YES - Using the HDS, check for these problems:
- Faulty PCM.
- Faulty immobilizer control unit-receiver.
NO - Go to step 15.
15. Try to start the engine with an un-proper key for the immobilizer system.
Does the engine start?
YES - Using the HDS, check for these problems:
- An open in the RED wire.
- Faulty PCM.
- Faulty immobilizer control unit-receiver.
NO - Faulty ignition key.