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Home >> Acura >> 2004 >> TL Automatic >> 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. 2 (15 A) fuse in the under-dash fuse/ relay box.

    Is the fuse OK? 

    1. YES  - Go to step 2.
    2. NO  - Replace the fuse.
  2. Remove the ignition coil relay from the under-dash fuse/relay box, 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, then terminal No. 4 and body ground.
    Fig 1: Measuring Voltage Between Ignition Coil Relay 4P Socket Terminal 1 & Body Ground And Terminal 4 & Body Ground
    G03653684Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there battery voltage? 

    1. YES   - Go to step 4.
    2. NO  - Replace the under-dash fuse/relay box.
  4. 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 4P Socket Terminals 2 And 1 Ignition Coil 3P Connector No. 3
    G03653685Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES  - Go to step 5.
    2. NO  - Repair an open in the wire between ignition coil relay 4P socket terminal No. 2 and No. 1 ignition coil 3P connector terminal No. 3.
  5. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 in HOW TO USE THE HDS (HONDA DIAGNOSTIC SYSTEM) ). 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 engine control module (ECM)/powertrain control module (PCM) from damage.
  6. Disconnect ECM/PCM connector E (31P) (2004-2005 models) or PCM connector A (31P) (2006 model).
  7. 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 3 And Body Ground
    G03653686Courtesy 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 ECM/ PCM (E20 (2004-2005 models) or A20 (2006 model)).
    2. NO  - Go to step 8.
  8. Check for continuity between ignition coil relay 4P socket terminal No. 3 and ECM/PCM connector terminal E20 (2004-2005 models) or A20 (2006 model).
    Fig 4: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No. 3 And ECM/PCM Connector Terminal E20 (2004-2005 Models)
    G03653687Courtesy of AMERICAN HONDA MOTOR CO., INC.
    Fig 5: Checking Continuity Between Ignition Coil Relay 4P Socket Terminal No. 3 And ECM/PCM Connector Terminal A20 (2006 Model)
    G03653688Courtesy 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 ECM/PCM (E20 (2004-2005 models) or A20 (2006 model)).
    2. NO  - Repair an open in the wire between ignition coil relay 4P socket terminal No. 3 and the ECM/ PCM (E20 (2004-2005 models) or A20 (2006 model)).
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