Operation CHARM: Car repair manuals for everyone.

Ignition System: Testing and Inspection

Ignition Coil Relay Circuit Troubleshooting

1. Check the No. 2 (15 A) fuse in the under-dash fuse/relay box.

Is the fuse OK?

YES - 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-dash fuse/reley box and the ignition coils.

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

Is the relay OK?

YES - Go to step 3.

NO - Replace the ignition coil relay.




3. Measure the voltage between ignition coil relay 4P socket terminal No. 1 and body ground, then terminal No. 4 and body ground.

Is there battery voltage?

YES - Go to step 4.

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




4. Check for continuity between ignition coil relay 4P socket terminal No. 2 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 4Psocket terminal No. 2 and each ignition coil 3P connector terminal No. 3.




5. Check for continuity between each ignition coil 3P connector terminal No. 2 and 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. 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 engine control module (ECM)/powertrain control module (PCM) (E7).

NO - Go to step 7.




7. Check for continuity between ignition coil relay 4P socket terminal No. 3 and ECM/PCM connector terminal E7.

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/PCM (E7).

NO - Repair open in the wire between ignition coil relay 4P socket terminal No. 3 and the ECM/PCM (E7).