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Home >> Infiniti >> 2008 >> G35 Base >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0850 Through P2A03 >> DTC P1564: ASCD Steering Switch >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK GROUND CONNECTION
    1. Turn ignition switch OFF.
    2. Check ground connection M95. Refer to Ground Inspection in "CIRCUIT INSPECTION ".

    Is the inspection result normal? 

    YES: GO TO 2.

    NO: Repair or replace ground connection.

  2. CHECK ASCD STEERING SWITCH CIRCUIT

    With CONSULT-III 

    1. Turn ignition switch ON.
    2. Select "MAIN SW""CANCEL SW""RESUME/ACC SW" and "SET SW" in "DATA MONITOR" mode with CONSULT-III.
    3. Check each item indication under the following conditions.
      DATA MONITOR

      Monitor item Condition Indication
      MAIN SW MAIN switch Pressed ON
      Released OFF
      CANCEL SW CANCEL switch Pressed ON
      Released OFF
      RESUME/ACC SW RESUME/ACCELERATE switch Pressed ON
      Released OFF
      SET SW SET/COAST switch Pressed ON
      Released OFF

    Without CONSULT-III 

    1. Turn ignition switch ON.
    2. Check the voltage between ECM harness connector and ground.
      TERMINALS VOLTAGE REFERENCE

      ECM Ground Condition Voltage
      Connector Terminal
      M107 101 (ASCD steering switch signal) Ground MAIN switch: Pressed Approx. 0V
      CANCEL switch: Pressed Approx. 1V
      SET/COAST switch: Pressed Approx. 2V
      RESUME/ACCELERATE switch: Pressed Approx. 3V
      All ASCD steering switches: Released Approx. 4V

    Is the inspection result normal? 

    YES: GO TO  8.

    NO: GO TO 3.

  3. CHECK ASCD STEERING SWITCH GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect combination switch harness connector M303.
    4. Check the continuity between combination switch and ECM harness connector.
      TERMINALS CONTINUITY REFERENCE

      Combination switch ECM Continuity
      Terminal Connector Terminal
      16 M107 108 Existed
    5. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO  5.

    NO: GO TO 4.

  4. DETECT MALFUNCTIONING PART

    Check the following.

    • Combination switch (spiral cable)
    • Harness for open and short between ECM and combination switch

      Repair open circuit or short to ground or short to power in harness or connectors.

  5. CHECK ASCD STEERING SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Check the continuity between combination switch and ECM harness connector.
      TERMINALS CONTINUITY REFERENCE

      Combination switch ECM Continuity
      Terminal Connector Terminal
      13 M107 101 Existed
    2. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO  7.

    NO: GO TO 6.

  6. DETECT MALFUNCTIONING PART

    Check the following.

    • Combination switch (spiral cable)
    • Harness for open and short between ECM and combination switch

      Repair open circuit or short to ground or short to power in harness or connectors.

  7. CHECK ASCD STEERING SWITCH

    Refer to "COMPONENT INSPECTION ".

    Is the inspection result normal? 

    YES: GO TO 8.

    NO: Replace ASCD steering switch.

  8. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    INSPECTION END

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