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Home >> Infiniti >> 2013 >> M56 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P1087 To P2542 >> DTC P1572: ASCD Brake Switch >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK OVERALL FUNCTION-I 

    WITH CONSULT

    1. Turn ignition switch ON.
    2. Select "BRAKE SW1" in "DATA MONITOR" mode with CONSULT.
    3. Check "BRAKE SW1" indication under the following conditions.
      Monitor item Condition Indication
      BRAKE SW1 (ASCD brake switch) Brake pedal Slightly depressed OFF
      Fully released ON

    WITHOUT CONSULT

    1. Turn ignition switch ON.
    2. Check the voltage between ECM harness connector terminals as per the following.
      ECM Condition Voltage (V)
      Connector + -
      Terminal Terminal
      M160 147 (ASCD brake switch signal) 175 Brake pedal Slightly depressed Approx. 0
      Fully released Battery voltage

      Is the inspection result normal? 

      YES: GO TO 2.

      NO: GO TO  3.

  2. CHECK OVERALL FUNCTION-II 

    WITH CONSULT

    Select "BRAKE SW2" and check indication under the following conditions.

    Monitor item Condition Indication
    BRAKE SW2 (Stop lamp switch) Brake pedal Slightly depressed ON
    Fully released OFF

    WITHOUT CONSULT

    Check the voltage between ECM harness connector terminals under the following conditions.

    ECM Condition Voltage (V)
    Connector + -
    Terminal Terminal
    M160 158 (Stop lamp switch signal) 175 Brake pedal Slightly depressed Battery voltage
    Fully released Approx. 0

    Is the inspection result normal? 

    YES: GO TO  13.

    NO: GO TO  8.

  3. 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  5.

      NO: GO TO 4.

  4. 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.

  5. 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 M160 147 Existed
    4. 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.

    • 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.

  7. CHECK ASCD BRAKE SWITCH 

    Refer to "COMPONENT INSPECTION (ASCD BRAKE SWITCH) "

    Is the inspection result normal? 

    YES: GO TO  13.

    NO: Replace ASCD brake switch. Refer to "EXPLODED VIEW ".

  8. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect stop lamp switch harness connector.
    3. Check the voltage between stop lamp switch harness connector and ground.
      Stop lamp switch Ground Voltage
      Connector Terminal
      E110 1 Ground Battery voltage

      Is the inspection result normal? 

      YES: GO TO  10.

      NO: GO TO 9.

  9. DETECT MALFUNCTIONING PART 

    Check the following.

    • 10 A fuse (No. 7)
    • Harness for open or short between stop lamp switch and battery
    • Loose or poor connection for each connector and harness

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

  10. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check the continuity between stop lamp switch harness connector and ECM harness connector.
      Stop lamp switch ECM Continuity
      Connector Terminal Connector Terminal
      E110 2 M160 158 Existed
    3. Also check harness for short to ground and short to power.

      Is the inspection result normal? 

      YES: GO TO  12.

      NO: GO TO 11.

  11. DETECT MALFUNCTIONING PART 

    Check the following.

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

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

  12. CHECK STOP LAMP SWITCH 

    Refer to "COMPONENT INSPECTION (STOP LAMP SWITCH) ".

    Is the inspection result normal? 

    YES: GO TO 13.

    NO: Replace stop lamp switch. Refer to "EXPLODED VIEW ".

  13. CHECK INTERMITTENT INCIDENT 

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END

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