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Home › Infiniti › 2008 › QX56 AWD › Repair and Diagnosis › Engine Performance › Engine Control Systems › Engine Control System - DTCS P1148 To P2A03 › DTC P1572: ICC Brake Switch › Diagnosis Procedure

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.
      BRAKE PEDAL CONDITION CHART

      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 CONDITION CHART

      CONDITION VOLTAGE
      Brake pedal: Slightly depressed Approximately 0V
      Brake pedal: Fully released Battery voltage

    OK or NG 

    OK: GO TO 2.

    NG: GO TO  3.

    Fig 1: Checking Voltage Between ECM Terminal 108 (ASCD Brake Switch Signal) And Ground
    G05739640Courtesy of NISSAN MOTOR CO., U.S.A.
  2. CHECK OVERALL FUNCTION-II

    With CONSULT-III 

    Check "BRAKE SW2" indication in "DATA MONITOR" mode.

    BRAKE PEDAL CONDITION CHART

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

    Without CONSULT-III 

    Check voltage between ECM terminal 101 and ground under the following conditions.

    VOLTAGE REFERENCE CHART

    CONDITION VOLTAGE
    Brake pedal: Fully released Approximately 0V
    Brake pedal: Slightly depressed Battery voltage
    Fig 2: Checking Voltage Between ECM Terminal 101 And Ground
    G05739641Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    OK: GO TO  14.

    NG: GO TO  7.

  3. CHECK ICC BRAKE SWITCH POWER SUPPLY CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ICC brake switch harness connector.
    3. Turn ignition switch ON.
    4. Check voltage between ICC brake switch terminal 1 and ground with CONSULT-III or tester.

      Voltage: Battery voltage 

    OK or NG 

    OK: GO TO  5.

    NG: GO TO 4.

    Fig 3: Checking Voltage Between ICC Brake Switch Terminal 1 And Ground
    G05739642Courtesy of NISSAN MOTOR CO., U.S.A.
  4. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors M31, E152
    • Fuse block (J/B) connector M4
    • 10A fuse
    • Harness for open or short between ICC brake switch and fuse

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

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

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

  6. CHECK ICC BRAKE SWITCH

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO  14.

    NG: Replace ICC brake switch.

  7. CHECK DTC WITH ICC UNIT

    Refer to ERASING ON BOARD SELF-DIAGNOSIS .

    OK or NG 

    OK: GO TO 8.

    NG: Repair or replace.

  8. CHECK POWER SUPPLY CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect stop lamp switch harness connector.
      Fig 4: Identifying Stop Lamp Switch Harness Connector
      G05739643Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between stop lamp switch terminal 3 and ground with CONSULT-III or tester.

      Voltage: Battery voltage 

      Fig 5: Checking Voltage Between Stop Lamp Switch Terminal 1 And Ground
      G05739644Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Disconnect ICC brake hold relay.
      Fig 6: Identifying ICC Brake Hold Relay
      G05739645Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Check voltage between ICC brake hold relay terminal 7 and ground with CONSULT-III or tester.

      Voltage: Battery voltage 

    OK or NG 

    OK: GO TO  10.

    NG: GO TO 9.

    Fig 7: Checking Voltage Between ICC Brake Hold Relay Terminal 7 And Ground
    G05739646Courtesy of NISSAN MOTOR CO., U.S.A.
  9. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors M31, E152
    • Fuse block (J/B) connector M60
    • 10A fuse
    • 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.

  10. CHECK INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 4.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

    4. Also check harness for short to ground and short to power.
    5. Check harness continuity between ECM terminal 101 and ICC hold relay terminal 6.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

    6. Also check harness for short to ground and short to power.
    7. Disconnect ICC unit harness connector.
    8. Check harness continuity between ECM terminal 101 and ICC unit terminal 38.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO  12.

    NG: GO TO 11.

  11. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E34, B40
    • Harness for open or short between ICC unit and ECM

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

  12. CHECK STOP LAMP SWITCH

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    OK: GO TO 13.

    NG: Replace stop lamp switch.

  13. CHECK ICC BRAKE HOLD RELAY

    Refer to "COMPONENT INSPECTION ".

    OK: GO TO 14.

    NG: Replace ICC brake hold relay.

  14. CHECK INTERMITTENT INCIDENT

    Refer to "HOW TO CHECK TERMINAL " and "INTERMITTENT INCIDENT ".

    INSPECTION END 

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