Ignition System: Testing and Inspection

Ignition Coil Relay Circuit Troubleshooting

1. Check the No. 16 (15 A) fuse in the under-dash 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-dash fuse/relay box and the ignition coil relay.�

2. Remove the ignition coil relay, and test it Testing and Inspection.

Is the relay OK?

YES -

Go to step 3.

NO -

Replace the ignition coil relay.�

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





Is there battery voltage?

YES -

Go to step 4.

NO -

Repair an open in the wire between under-dash fuse/relay box and ignition coil relay.�

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





Is there continuity?

YES -

Go to step 5.

NO -

Repair an 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 body ground.





Is there continuity?

YES -

Go to step 6.

NO -

Repair an open in the wire between ignition coil 3P connector terminal No. 2 and body ground G102.�

6. Connect the HDS to the DLC.

7. Turn the ignition switch to ON (II).

8. Make sure the HDS communicates with the vehicle and the ECM/PCM. If it does not communicate, troubleshoot the DLC circuit Testing and Inspection.

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/ PCM from damage.

10. Disconnect ECM/PCM connector E (31P).

11. Check for continuity between ignition coil relay 4P socket terminal No. 3 and body ground.





Is there continuity?

YES -

Repair a short in the wire between ignition coil relay 4P socket terminal No. 3 and ECM/PCM connector terminal E7.�

NO -

Go to step 12.

12. 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 ECM/PCM connector terminal E7.�

NO -

Repair an open in the wire between ignition coil relay 4P socket terminal No. 3 and ECM/PCM connector terminal E7.�