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Home >> Infiniti >> 2023 >> QX80 Premium Select, AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System (Diagnostics) (1 Of 2) >> Component Parts /Circuit Diagnosis >> ASCD Brake Switch >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK ASCD BRAKE SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ASCD brake switch harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between ASCD brake switch harness connector and ground.

      ASCD brake switch

      Ground

      Voltage

      Connector

      Terminal

      E109

      1

      Ground

      Battery voltage

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    GO TO 2.

  2. DETECT MALFUNCTIONING PART 

    Check the following.

    • 10 A fuse (No. 3)
    • Harness for open or short between ASCD brake switch and fuse
    • Loose or poor connection for each connector and harness

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

  3. CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between ASCD brake switch harness connector and ECM harness connector.

      ASCD brake switch

      ECM

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      E109

      2

      E20

      140

      Existed

    4. 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.

    • Harness for open or short between ECM and ASCD brake switch
    • Loose or poor connection for each connector and harness

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

  5. CHECK ASCD BRAKE SWITCH 

    Refer to Component Inspection .

    Is the inspection result normal?

    YES

    GO TO 6.

    NO

    Replace ASCD brake switch. Refer to BRAKE PEDAL : Removal & Installation .

  6. CHECK INTERMITTENT INCIDENT 

    Refer to Inspection .

    INSPECTION END