Ignition System: Testing and Inspection

Ignition Coil Relay Circuit Troubleshooting

1. Check the No. 18 (15 A) fuse in the under-hood fuse/relay box.

Is the fuse OK?

YES - Reinstall the fuse, then go to step 2.

NO - Replace the fuse. If the fuse continues to blow, locate and repair the short in the circuit between the under-hood fuse/relay box and the ignition coils.

2. Remove the ignition coil relay from the under-hood fuse/relay box, and test it.

Is the relay OK?

YES - Reinstall the fuse, then to step 3.

NO - Replace the ignition coil relay.

3. Measure the voltage between ignition coil relay 4P socket terminal No. 2 and body ground, then terminal No. 4 and body ground.






Is there battery voltage?

YES - Go to step 4.

NO - Replace the under-hood fuse/relay box.

4. Check for continuity between each ignition coil relay 4P socket terminal No. 1 and the each ignition coil 3P connector terminal No. 3.






Is there continuity?

YES - Go to step 5.

NO - Repair open in the wire between ignition coil relay 4P socket terminal No. 1 and ignition coil 3P connector terminal No. 3.

5. Check for continuity between each ignition coil 3P connector terminal No. 2 and the body ground.






Is there continuity?

YES - Go to step 6.

NO - Repair open in the wire between ignition coil 3P connector terminal No. 2 and the body ground.

6. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC).
7. Turn the ignition switch to ON (II).
8. Make sure the HDS communicates with the vehicle and the engine control module (ECM). If it doesn't communicate, troubleshoot the DLC circuit.
9. Jump the SCS line with the HDS, then turn the ignition switch to LOCK (0).

NOTE: This step must be done to protect the ECM from damage.

10. Disconnect ECM connector A (44P).
11. Check for continuity between ignition coil relay 4P socket terminal No. 3 and body ground.






Is there continuity?

YES - Repair short in the wire between ignition coil relay 4P socket terminal No. 3 and the ECM (A6).

NO - Go to step 12.

12. Check for continuity between ignition coil relay 4P socket terminal No. 3 and ECM connector terminal A6.






Is there continuity?

YES - The system is OK at this time. Check for loose or poor connections at the ignition coil relay and the ECM (A6).

NO - Repair open in the wire between ignition coil relay 4P socket terminal No. 3 and the ECM (A6).