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Home >> Honda >> 2006 >> Civic Si >> Repair and Diagnosis >> Engine Performance >> System >> Idle Control System (K20Z3 Engine) >> Alternator FR Signal Circuit Troubleshooting

Alternator FR Signal Circuit Troubleshooting

  1. Start the engine, and let it idle.
  2. Monitor the ALTERNATOR in the DATA LIST with the HDS.
  3. Check if the indicated percentage varies when the headlight switch is turned on.

    Does the percentage vary? 

    YES  -The alternator signal circuit is OK.

    NO  -Go to step 4.

  4. Turn the headlight switch and ignition switch OFF.
  5. Jump the SCS line with the HDS.
  6. Disconnect the alternator 4P connector.
  7. Disconnect ECM connector B (44P).
  8. Check for continuity between body ground and ECM connector terminal B43.
    Fig 1: Checking Continuity Between Body Ground And ECM Connector Terminal B43
    G04666084Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  -Repair short in the wire between the ECM (B43) and the alternator.

    NO  -Update the ECM if it does not have the latest software (see ECM UPDATE ), or substitute a known-good ECM (see SUBSTITUTING THE ECM ), then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM (see ECM REPLACEMENT ).