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Home › Infiniti › 2012 › QX56 AWD › Repair and Diagnosis › Engine Performance › System › Engine Control System - DTCS P1550 To P2A03 › DTC P1564: ASCD Steering Switch › Diagnosis Procedure

Diagnosis Procedure

  1. CHECK ASCD STEERING SWITCH CIRCUIT

    WITH CONSULT

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

    1. Turn ignition switch ON.
    2. Check the voltage between ECM harness connector terminals under the following conditions.
    ECM Condition Voltage (V)
    Connector + -
    Terminal terminal
    E80 128 (ASCD steering switch signal) 130 MAIN switch: Pressed Approx. 0
    CANCEL switch: Pressed Approx. 1
    SET/COAST switch: Pressed Approx. 2
    RESUME/ACCELERATE switch: Pressed Approx. 3
    All ASCD steering switches: Released Approx. 4

    Is the inspection result normal? 

    YES: GO TO  7.

    NO: GO TO 2.

  2. 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.
    4. Check the continuity between combination switch and ECM harness connector.
      Combination switch ECM Continuity
      Connector Terminal Connector terminal
      - 32 E80 130 Existed
    5. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO  4.

    NO: GO TO 3.

  3. DETECT MALFUNCTIONING PART

    Check the following.

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

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

  4. CHECK ASCD STEERING SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Check the continuity between combination switch and ECM harness connector.
      Combination switch ECM Continuity
      Connector Terminal Connector terminal
      - 25 E80 128 Existed
    2. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO  6.

    NO: GO TO 5.

  5. DETECT MALFUNCTIONING PART

    Check the following.

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

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

  6. CHECK ASCD STEERING SWITCH

    Refer to "COMPONENT INSPECTION (ASCD STEERING SWITCH) ".

    Is the inspection result normal? 

    YES: GO TO 7.

    NO: Replace ASCD steering switch. Refer to "REMOVAL AND INSTALLATION ".

  7. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END

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