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Home >> Infiniti >> 2008 >> FX35 AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - Component System Testing (VQ35DE) >> ASCD Brake Switch >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK OVERALL FUNCTION-I 

    With CONSULT-III 

    1. Turn ignition switch ON.
    2. Select "BRAKE SW1" in "DATA MONITOR" mode with CONSULT-III.
    3. Check "BRAKE SW1" indication under the following conditions.
    BRAKE SWITCH INDICATION AND BRAKE PEDAL CONDITION

    CONDITION INDICATION
    Brake pedal: Slightly depressed OFF
    Brake pedal: Fully released ON

    Without CONSULT-III 

    1. Turn ignition switch ON.
    2. Check voltage between ECM terminal 108 and ground under the following conditions.
    BRAKE PEDAL POSITION AND VOLTAGE REFERENCE

    CONDITION VOLTAGE
    Brake pedal: Slightly depressed Approximately 0V
    Brake pedal: Fully released Battery voltage
    Fig 1: Checking Voltage Between ECM Terminal 108 And Ground
    G04900670Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO INSPECTION END  .

    NG: GO TO  2.

  2. CHECK ASCD BRAKE SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ASCD brake switch harness connector.
    3. Turn ignition switch ON.
      Fig 2: Identifying ASCD Brake Switch And Stop Lamp Switch
      G05216810Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between ASCD brake switch terminal 1 and ground with CONSULT-III or tester.

      Voltage: Battery voltage 

    OK or NG 

    OK: GO TO  4.

    NG: GO TO  3.

    Fig 3: Checking Voltage Between ASCD Brake Switch Terminal 1 And Ground
    G04875403Courtesy of NISSAN MOTOR CO., U.S.A.
  3. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector E201
    • 10A fuse
    • Harness for open or short between ASCD brake switch and fuse

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

  4. CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between ECM terminal 108 and ASCD brake switch terminal 2.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO  6.

    NG: GO TO  5.

  5. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E211, M41
    • Harness for open or short between ECM and ASCD brake switch

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

  6. CHECK ASCD BRAKE SWITCH 

    Refer to "Component Inspection "

    OK or NG 

    OK: GO TO  7.

    NG: Replace ASCD brake switch.

  7. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    >> INSPECTION END 

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