Immobilizer System Troubleshooting

Follow this procedure if the vehicle does not start after rewriting the ECM/PCM with the Honda PGM tester or the HDS.

Note these items before troubleshooting:


1.Using a Honda PGM Tester or the 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.n


NO - Go to 2.


2.Remove the steering column covers.

3.Disconnect the 7P connector (A) from the immobilizer control unit-receiver (B).

4.Turn the ignition switch ON (II) with the proper key.

5.Check to see if the immobilizer indicator comes on.

Does the indicator come on (blinking or solid)?


YES - Go to 6.


NO - Go to 9.


6.Check for voltage between the immobilizer control unit-receiver 7P connector No. 7 terminal and body ground.

Is there battery voltage?


YES - Go to 7.


NO - Check for these problems:

  • A blown No. 15 (40A) fuse in the under-hood fuse/relay box.n
  • A blown No. 7 (10A) fuse in the under-dash fuse/relay box.n
  • An open in the WHT wire.n


7.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 8.


NO - Check for these problems:

  • Short to ground.n
  • Faulty parking brake switch or a poor body ground of the  parking brake switch.n
  • Repair an open in the GRN wire.n


8.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 9.


NO - Repair an open in the RED wire.n

9.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 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.


10.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 11.


NO - Check for these problems:

  • An open in the BLU (or BLU/ORN) wire between the gauge assembly and immobilizer control unit-receiver.n
  • A faulty immobilizer indicator light.n
  • A blown No. 21 (7.5A) fuse in the under-dash fuse/relay box.n


11.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 12.


NO - Check for these problems:

  • A blown No. 19 (15A) fuse in the under-dash fuse/relay box.n
  • An open in the BLK/YEL wire.n


12.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 Honda PGM Tester or HDS.n


NO - Repair the open in the BRN/YEL wire.n