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Home >> Infiniti >> 2004 >> I35 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> DTC P1574: ASCD Vehicle Speed Sensor >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK TCM FUNCTION 

    Check malfunction of the AT system with CONSULT-II or O/D OFF indicator. Refer to AUTOMATIC TRANSAXLE .

    OK or NG 

    1. OK: GO TO 2.
    2. NG: Check AT system. Refer to AUTOMATIC TRANSAXLE .
  2. CHECK SPEEDOMETER OPERATION 

    Check if speedometer operates normally.

    OK or NG 

    1. OK: GO TO 3.
    2. NG: Check speedometer and vehicle speed sensor circuit. Refer to METERS AND GAUGES .
  3. CHECK VEHICLE SPEED SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector and combination meter harness connector.
    3. Check harness continuity between ECM terminal 68 and combination meter terminal 32 with CONSULT-II or tester. Refer to Wiring Diagram.

      Continuity should exist. 

    4. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  5 .
    2. NG: GO TO 4.
  4. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors F66, M229
    • Harness for open or short between combination meter and ECM
    • : Repair open circuit or short to ground or short to power in harness or connectors.
  5. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  .

    1. : INSPECTION END
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