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Home >> Infiniti >> 2008 >> G35 Base >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0850 Through P2A03 >> DTC P1572: ASCD Brake Switch >> Diagnosis Procedure
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Diagnosis 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.
      DATA MONITOR

      Monitor item Condition Indication
      BRAKE SW1 Brake pedal (A/T) Brake pedal and clutch pedal (M/T) Slightly depressed OFF
      Fully released ON

    Without CONSULT-III 

    1. Turn ignition switch ON.
    2. Check the voltage between ECM harness connector and ground.
      TERMINALS VOLTAGE REFERENCE

      ECM Ground Condition Voltage
      Connector Terminal
      M107 126 (ASCD brake switch signal) Ground Brake pedal (A/T)
      Brake pedal and clutch pedal (M/T)      		 Slightly depressed Approx. 0V
      Fully released Battery voltage

    Is the inspection result normal? 

    YES: GO TO 2.

    NO-1: A/T models: GO TO  3.

    NO-2: M/T models: GO TO  8.

  2. CHECK OVERALL FUNCTION-II

    With CONSULT-III 

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

    BRAKE SW2 REFERENCE

    Monitor item Condition Indication
    BRAKE SW2 Brake pedal Slightly depressed ON
    Fully released OFF

    Without CONSULT-III 

    Check the voltage between ECM harness connector and ground.

    TERMINALS VOLTAGE REFERENCE

    ECM Ground Condition Voltage
    Connector Terminal
    M107 122 (Stop lamp switch signal) Ground Brake pedal Slightly depressed Battery voltage
    Fully released Approx. 0V

    Is the inspection result normal? 

    YES: GO TO  21.

    NO: GO TO  16.

  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.
      TERMINALS VOLTAGE REFERENCE

      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
    • 10A 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.
      TERMINALS CONTINUITY REFERENCE

      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 or 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  21.

    NO: Replace ASCD brake switch.

  8. CHECK ASCD BRAKE SWITCH CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ASCD clutch switch harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between ASCD clutch switch harness connector and ground.
      TERMINALS VOLTAGE REFERENCE

      ASCD clutch switch Ground Condition Voltage
      Connector Terminal
      E108 2 Ground Brake pedal Slightly depressed Approx. 0V
      Fully released Battery voltage

    Is the inspection result normal? 

    YES: GO TO  13.

    NO: GO TO 9.

  9. 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.
      TERMINALS VOLTAGE REFERENCE

      ASCD brake switch Ground Voltage
      Connector Terminal
      E109 1 Ground Battery voltage

    Is the inspection result normal? 

    YES: GO TO  11.

    NO: GO TO 10.

  10. DETECT MALFUNCTIONING PART

    Check the following.

    • Fuse block (J/B) connector E103
    • 10A 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.

  11. CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Check the continuity between ASCD brake switch harness connector and ASCD clutch switch harness connector.
      TERMINALS CONTINUITY REFERENCE

      ASCD brake switch ASCD clutch switch Continuity
      Connector Terminal Connector Terminal
      E109 2 E108 2 Existed
    3. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO 12.

    NO: Repair open circuit or short to ground or short to power in harness or connectors.

  12. CHECK ASCD BRAKE SWITCH

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

    Is the inspection result normal? 

    YES: GO TO  21.

    NO: Replace ASCD brake switch.

  13. 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 clutch switch harness connector and ECM harness connector.
      TERMINALS CONTINUITY REFERENCE

      ASCD clutch switch ECM Continuity
      Connector Terminal Connector Terminal
      E108 1 M107 126 Existed
    4. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO  15.

    NO: GO TO 14.

  14. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E106, M6
    • Harness for open or short between ECM and ASCD clutch switch

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

  15. CHECK ASCD CLUTCH SWITCH

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

    Is the inspection result normal? 

    YES: GO TO  21.

    NO: Replace ASCD clutch switch.

  16. 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.
      TERMINALS VOLTAGE REFERENCE

      Stop lamp switch Ground Voltage
      Connector Terminal
      E110 1 Ground Battery voltage

    Is the inspection result normal? 

    YES: GO TO  18.

    NO: GO TO 17.

  17. 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 or short to ground or short to power in harness or connectors.

  18. 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.
      TERMINALS CONTINUITY REFERENCE

      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  20.

    NO: GO TO 19.

  19. 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 or short to ground or short to power in harness or connectors.

  20. CHECK STOP LAMP SWITCH

    Refer to "COMPONENT INSPECTION (STOP LAMP SWITCH) "

    Is the inspection result normal? 

    YES: GO TO 21.

    NO: Replace stop lamp switch.

  21. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    INSPECTION END

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