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Home >> Infiniti >> 2005 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> DTC P1572: ICC Brake Switch >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK OVERALL FUNCTION-1 

    With CONSULT-II 

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

      CONDITION INDICATION
      Brake pedal: Slightly depressed OFF
      Brake pedal: Fully released ON
      Fig 1: CONSULT-II Display - "BRAKE SW1" in "DATA MONITOR" Mode
      G02389292Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

    1. Turn ignition switch ON.
    2. Check voltage between ECM terminal 108 and ground under the following conditions.
      ICC BRAKE SWITCH CONDITION - VOLTAGE

      CONDITION VOLTAGE
      Brake pedal: Slightly depressed Approximately 0V
      Brake pedal: Fully released Battery voltage
      Fig 2: Checking Voltage Between ECM Terminal 108 And Ground
      G02389293Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 2.
    2. NG: GO TO  3.
  2. CHECK OVERALL FUNCTION-II 

    With CONSULT-II 

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

    ICC BRAKE SWITCH CONDITION - INDICATION

    CONDITION INDICATION
    Brake pedal: Fully released OFF
    Brake pedal: Slightly depressed ON
    Fig 3: CONSULT-II Display - "BRAKE SW2" Indication In "DATA MONITOR" Mode
    G02389294Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

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

    ICC BRAKE SWITCH CONDITION - VOLTAGE

    CONDITION VOLTAGE
    Brake pedal: Fully released Approximately 0V
    Brake pedal: Slightly depressed Battery voltage
    Fig 4: Checking Voltage Between ECM Terminal 101 And Ground
    G02389295Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO  14.
    2. NG: GO TO  10.
  3. CHECK DTC WITH ICC UNIT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    OK or NG 

    1. OK: GO TO 4.
    2. NG: Repair or replace.
  4. CHECK ICC BRAKE HOLD RELAY POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ICC brake hold relay.
    3. Turn ignition switch ON.
      Fig 5: Identifying Battery And ICC Brake Hold Relay
      G02389296Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between ICC brake hold relay terminal 4 and ground with CONSULT-II or tester.
      1. Voltage: Battery voltage 

    OK or NG 

    1. OK: GO TO  6.
    2. NG: GO TO 5.
    Fig 6: Checking Voltage Between ICC Brake Hold Relay Terminal 4 And Ground
    G02389297Courtesy of NISSAN MOTOR CO., U.S.A.
  5. 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 hold relay and fuse
      1. Repair open circuit or short to ground or short to power in harness or connectors.
  6. CHECK ICC BRAKE SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ICC brake switch harness connector.
    3. Check harness continuity between ICC brake hold relay terminal 3 and ICC brake switch terminal 1.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    4. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO 7.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
    Fig 7: Identifying ICC Brake Switch, Stop Lamp Switch And Brake Pedal
    G02389298Courtesy of NISSAN MOTOR CO., U.S.A.
  7. CHECK ICC BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ICC brake switch terminal 2 and ECM terminal 108.

      Refer Wiring Diagram.

      1. Continuity should exist. 
    3. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO 8.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
  8. CHECK ICC BRAKE HOLD RELAY 

    Refer to "COMPONENT INSPECTION ".

    1. OK: GO TO 9.
    2. NG: Replace ICC brake hold relay.
  9. CHECK ICC BRAKE SWITCH 

    Refer to "COMPONENT INSPECTION ".

    OK or NG 

    1. OK: GO TO  14.
    2. NG: Replace ICC brake switch.
  10. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect stop lamp switch harness connector.
      Fig 8: Identifying ICC Brake Switch, Stop Lamp Switch And Brake Pedal
      G02389299Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between stop lamp switch terminal 3 and ground with CONSULT-II or tester.
      1. Voltage: Battery voltage 

    OK or NG 

    1. OK: GO TO  12.
    2. NG: GO TO 11.
    Fig 9: Checking Voltage Between Stop Lamp Switch Terminal 3 And Ground With Consult-II
    G02389300Courtesy of NISSAN MOTOR CO., U.S.A.
  11. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors M31, E152
    • Fuse block (J/B) No. 1 connector M60
    • 10A fuse
    • Harness for open or short between stop lamp switch and battery
      1. Repair open circuit or short to ground or short to power in harness or connectors.
  12. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 4.

      Refer to WIRING DIAGRAM .

      1. Continuity should exist. 
    3. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO 13.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
  13. CHECK STOP LAMP SWITCH 

    Refer to "COMPONENT INSPECTION "

    OK or NG 

    1. OK: GO TO 14.
    2. NG: Replace stop lamp switch.
  14. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    1. : INSPECTION END 
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