Ignition Coil Relay Circuit Troubleshooting

Check the No. 18 (15 A) fuse in the under-hood 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-hood fuse/relay box and the ignition coils.
Remove the ignition coil relay from the under-hood fuse/relay box, and test it (see POWER RELAY TEST ).
Is the relay OK?

YES -Go to step 3.

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

Fig 1: Measuring Voltage Between Ignition Coil Relay 4P Socket Terminal No 2 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 4.

NO -Replace the under-hood fuse/relay box.
Check for continuity between ignition coil relay 4P socket terminal No. 2 and the No. 1 ignition coil 3P connector terminal No. 3.

Fig 2: Checking Continuity Between Ignition Coil Relay Terminal 2 And Ignition Coil Terminal 3
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 5.

NO -Repair open in the wire between ignition coil relay 4P socket terminal No. 2 and ignition coil 3P connector terminal No. 3.
Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 under HOW TO USE THE HDS (HONDA DIAGNOSTIC SYSTEM) ).
Turn the ignition switch ON (II).
Make sure the HDS communicates with the vehicle and the powertrain control module (PCM). If it doesn't, troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).
Jump the SCS line with the HDS, then turn the ignition switch OFF.
NOTE: This step must be done to protect the PCM from damage.
Disconnect PCM connector A (44P).
Check for continuity between ignition coil relay 4P socket terminal No. 3 and body ground.

Fig 3: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No 3 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

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

NO -Go to step 11.
Check for continuity between ignition coil relay 4P socket terminal No. 3 and PCM connector terminal A6.

Fig 4: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal 3 And PCM Terminal A6
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

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

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