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Home >> Acura >> 2007 >> MDX >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Idle Control System >> Alternator FR Signal Circuit Troubleshooting
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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 to LOCK (0).
  5. Jump the SCS line with the HDS.
  6. Disconnect the alternator 4P connector.
  7. Disconnect PCM connector C (49P).
  8. Check for continuity between body ground and PCM connector terminal C44.
    Fig 1: Identifying Continuity Between Body Ground And PCM Connector Terminal C44
    G05485206Courtesy of AMERICAN HONDA MOTOR CO., INC.

    Is there continuity? 

    YES  - Repair short in the wire between the PCM (C44) and the alternator.

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