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K20A3 Engine

  1. Check for proper operation of the electrical load detector (ELD) by checking the malfunction indicator lamp (MIL) (see GENERAL TROUBLESHOOTING INFORMATION ).
  2. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC), and check for DTCs (see step 2 on IF THE MIL (MALFUNCTION INDICATOR LAMP) HAS COME ON ). If a DTC is present, diagnose and repair the cause before continuing with this test.
  3. Disconnect the engine wire harness 8P connector from the starter subharness 8P connector.
  4. Start the engine, and turn on the headlights to high beam.
  5. Measure the voltage between engine wire harness 8P connector terminal No. 3 and the positive terminal of the battery.
    Fig 1: Measuring Voltage Between Engine Wire Harness 8P Connector Terminal No. 3 And Positive Terminal Of Battery
    G03650066Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there 1 V or less? 

    1. YES -  Go to step 6.
    2. NO -  Go to step  9.
  6. Jump the SCS line with the HDS, then turn off the headlights and ignition switch.
    NOTE: This step must be done to protect the engine control module (ECM)/powertrain control module (PCM) from damage.
  7. Disconnect ECM/PCM connector B (24P).
  8. Check for continuity between ECM/PCM connector terminal B18 and body ground.

    2002-2004 Models 

    Fig 2: Checking For Continuity Between ECM/PCM Connector Terminal B18 And Body Ground - 2002-2004 Models
    G03650067Courtesy of AMERICAN HONDA MOTOR CO., INC.

    2005-2006 Models 

    Fig 3: Checking For Continuity Between ECM/PCM Connector Terminal B18 And Body Ground - 2005-2006 Models
    G03650068Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Repair a short in the wire between the alternator and the ECM/PCM.
    2. NO -  Update the ECM/PCM if it does not have the latest software (see HOW TO UPDATE THE ECM/PCM ), or substitute a known-good ECM/PCM (see HOW TO SUBSTITUTE THE ECM/PCM (2002-2004 MODELS) ), then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM (see ECM/PCM REPLACEMENT ).
  9. Jump the SCS line with the HDS, then turn off the headlights and ignition switch.
    NOTE: This step must be done to protect the ECM/PCM for damage.
  10. Disconnect ECM/PCM connector B (24P).
  11. Check for continuity between ECM/PCM connector terminal B18 and the engine wire harness 8P connector terminal No. 3.

    2002-2004 Models 

    Fig 4: Checking For Continuity Between ECM/PCM Connector Terminal B18 And Engine Wire Harness 8P Connector Terminal No. 3 - 2002-2004 Models
    G03650069Courtesy of AMERICAN HONDA MOTOR CO., INC.

    2005-2006 Models 

    Fig 5: Checking For Continuity Between ECM/PCM Connector Terminal B18 And Engine Wire Harness 8P Connector Terminal No. 3 - 2005-2006 Models
    G03650070Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    1. YES -  Replace the alternator (see ALTERNATOR REMOVAL AND INSTALLATION  ) or repair the alternator (see ALTERNATOR OVERHAUL  ).
    2. NO -  Repair an open in the wire between the alternator and the ECM/PCM.
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