Immobilizer System Troubleshooting

Follow this procedure if the vehicle does not start after rewriting the ECM/PCM with the HDS. Note these items before troubleshooting: Due to the action of the immobilizer system, the engine takes slightly more time to start than vehicle's 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, or if the engine does not start, repeat the starting procedure. If the engine still does not start, continue with this procedure. Using a HDS, check for a Diagnostic Trouble Code (DTC). Is DTC P1607 indicated?
YES − | - | Substitute the ECM/PCM with a known-good ECM/PCM and retest. ■
NO | - | Go to Step 2 .
Remove the steering column covers. Disconnect the 7P connector (A) from the immobilizer control unit-receiver (B). Turn the ignition switch ON (II) with the proper key. Check to see if the immobilizer indicator comes on. Does the indicator come on (blinking or solid)?
YES | - | Go to Step 6 .
NO | - | Go to Step 9 .
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 7 .
NO | - | Check for these problems: A blown No. 15 (40 A) fuse in the under-hood fuse/relay box.■ A blown No. 7 (10 A) fuse in the under-dash fuse/relay box.■ An open in the WHT wire.■
Check for voltage between the immobilizer control-unit receiver 7P connector No. 4 terminal and body ground with the parking brake lever pulled, then released. Is there 1 V or less, then 5 V or more?
YES | - | Go to Step 8 .
NO | - | Check for these problems: Short to ground.■ Faulty parking brake switch or a poor body ground of the parking brake switch .■ Repair an open in the GRN wire.■
Check for continuity between the immobilizer control unit-receiver 7P connector No. 2 terminal and ECM/PCM connector A27 terminal. Is there continuity?
YES | - | Go to Step 9 .
NO | - | Repair an open in the RED wire.■
Check for continuity between the immobilizer control unit-receiver 7P connector No. 2 terminal and the imoes unit connector terminal No. 2. Is there continuity?
YES | - | Go to Step 10 .
NO | - | Repair an open in the RED wire. If the harness is OK, check to see if there is there is any input test for the imoes unit.■
Connect the immobilizer control unit-receiver 7P connector No. 5 terminal to body ground with the ignition switch ON (II). Does the immobilizer indicator come on?
YES | - | Go to Step 11 .
NO | - | Check for these problems: An open in the BLU (or BLU/ORN) wire between the gauge assembly and immobilizer control unit-receiver.■ A faulty immobilizer indicator light.■ A blown No. 21 (7.5 A) fuse in the under-dash fuse/relay box.■
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 | - | Go to Step 12 .
NO | - | Check for these problems: A blown No. 19 (15 A) fuse in the under-dash fuse/relay box.■ An open in the BLK/YEL wire.■
Check for continuity between the immobilizer control unit-receiver 7P connector No. 1 terminal and body ground. Is there continuity?
YES | - | Replace the immobilizer control unit-receiver. After replacing the immobilizer control unit-receiver, rewrite the unit with a HDS.■
NO | - | Repair the open in the BRN/YEL wire.■