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Home >> Acura >> 2005 >> MDX Base >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Ignition Coil Relay Circuit Troubleshooting
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Ignition Coil Relay Circuit Troubleshooting

  1. Check the No. 46 (15 A) fuse in the under-hood fuse/relay box and No. 8 (15 A) fuse in the under-hood subfuse box.

    Is the fuse OK? 

    1. YES  - Go to step 2.
    2. NO  - Replace the fuse.
  2. Remove the ignition coil relay from the relay block, and test it (see POWER RELAY TEST ).

    Is the relay OK? 

    1. YES  - Go to step 3.
    2. NO  - Replace the ignition coil relay.
  3. Measure the voltage between ignition coil relay 4P socket terminal No. 1 and body ground.
    Fig 1: Measuring Voltage Between Ignition Coil Relay 4P Socket Terminal No. 1 And Body Ground
    G03639164Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Go to step 4.
    2. NO  - Repair an open in the wire between ignition coil relay 4P socket terminal No. 1 and the under-hood subfuse box.
  4. Measure the voltage between ignition coil relay 4P socket terminal No. 4 and body ground.
    Fig 2: Measuring Voltage Between Ignition Coil Relay 4P Socket Terminal No. 4 And Body Ground
    G03639165Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES  - Go to step 5.
    2. NO  - Repair an open in the wire between ignition coil relay 4P socket terminal No. 4 and the under-hood fuse/relay box.
  5. Check for continuity between ignition coil relay 4P socket terminal No. 2 and No. 1 ignition coil 3P connector terminal No. 3.
    Fig 3: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No. 2 And 1 Ignition Coil 3P Connector Terminal No. 3
    G03639166Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  - Go to step 6.
    2. NO  - Repair an open in the wire between ignition coil relay 4P socket terminal No. 2 and ignition coil 3P connector terminal No. 3.
  6. Check for continuity between ignition coil relay 4P socket terminal No. 3 and body ground.
    Fig 4: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No. 3 And Body Ground
    G03639167Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  - Repair a short in the wire between ignition coil relay 4P socket terminal No. 3 and the PCM (B12).
    2. NO  - Go to step 7.
  7. Turn the ignition switch OFF.
  8. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 on GENERAL TROUBLESHOOTING INFORMATION ). Turn the ignition switch ON (II), and jump the SCS line with the HDS, then turn the ignition switch OFF.
    NOTE: This step must be done to protect the powertrain control module (PCM) from damage.
  9. Disconnect PCM connector B (56P).
  10. Check for continuity between ignition coil relay 4P socket terminal No. 3 and PCM connector terminal B12.
    Fig 5: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No. 3 And PCM Connector Terminal B12
    G03639168Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  - The system is OK at this time. Check for loose or poor connections at the ignition coil relay and the PCM (B12).
    2. NO  - Repair an open in the wire between ignition coil relay 4P socket terminal No.3 and the PCM (B12).
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