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Home >> Infiniti >> 2013 >> EX37 Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P1225 To P2138 >> 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 Brake pedal Slightly depressed OFF
      Brake pedal 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
      M107 126
      (ASCD brake switch signal)      		 128 Brake pedal Slightly depressed Approx. 0
      Brake pedal 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 Brake pedal Slightly depressed ON
    Fully released OFF

    Without CONSULT 

    Check the voltage between ECM harness connector terminals as per the following.

    ECM Condition Voltage (V)
    Connector + -
    Terminal Terminal
    M107 122
    (Stop lamp switch signal)    		 128 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.

    • Fuse block (J/B) connector E103
    • 10 A fuse (No. 3)
    • Harness for open or short between ASCD brake switch and fuse

      : 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 M107 126 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 connectors E106, M6
    • Harness for open or short between ECM and ASCD brake switch

      : 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.

    • Fuse block (J/B) connector E103
    • 10A fuse (No. 7)
    • Harness for open or short between stop lamp switch and battery

      : 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 M107 122 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.

    • Fuse block (J/B) connectors E103, M2
    • Harness for open or short between ECM and stop lamp switch

      : 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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