LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2004 >> I35 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> DTC P1572: ASCD Brake Switch >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

  1. CHECK OVERALL FUNCTION-I 

    With CONSULT-II 

    1. Turn ignition switch ON
    2. Select BRAKE SW1 in DATA MONITOR mode with CONSULT-II.
    3. Check the indication of BRAKE SW1 under the following conditions.
      Fig 1: Display CONSULT-II DATA MONITOR Screen
      G00787353Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 2: Displaying Indication Of BRAKE SW1 Based On Conditions
      G00787354Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

    1. Turn ignition switch ON
    2. Check voltage between ECM terminal 59 and ground under the following conditions.
      Fig 3: Checking Voltage Between ECM And Ground
      G00787355Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 4: Displaying Voltage Indication Based On Conditions
      G00787356Courtesy of NISSAN MOTOR CO., U.S.A.

    Refer to Wiring Diagram.

    OK or NG 

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

    With CONSULT-II 

    See BRAKE SW2 indication in DATA MONITOR mode.

    Fig 5: Display CONSULT-II DATA MONITOR Screen
    G00787357Courtesy of NISSAN MOTOR CO., U.S.A.
    Fig 6: Displaying Indication Of BRAKE SW2 Based On Conditions
    G00787358Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

    Check voltage between ECM terminal 55 and ground under the following conditions.

    Fig 7: Checking Voltage Between ECM And Ground
    G00787359Courtesy of NISSAN MOTOR CO., U.S.A.

    Refer to Wiring Diagram.

    Fig 8: Displaying Voltage Indication Based On Conditions
    G00787360Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO  14 .
    2. NG: GO TO  9 .
  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 voltage between ASCD brake switch terminal 1 and ground with CONSULT-II or tester.
      Fig 9: Checking Voltage Between ASCD Brake Switch And Ground
      G00787361Courtesy of NISSAN MOTOR CO., U.S.A.

    Voltage: Battery voltage 

    OK or NG 

    1. OK: GO TO  5 .
    2. NG: GO TO 4.
  4. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector E83
    • 10A fuse
    • Harness for open or short between ASCD brake switch and fuse
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  5. CHECK ASCD BRAKE SWITCH INPUT CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between ECM terminal 59 and ASCD brake switch terminal 2.

      Refer to Wiring Diagram.

      Continuity should exist. 

    4. Also check harness for open to ground and short to power.

    OK or NG 

    1. OK: GO TO  9 .
    2. NG: GO TO 6.
  6. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E81, M15
    • Harness connectors M223, F53
    • Harness for open and short between ECM and ASCD brake switch
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  7. CHECK ASCD BRAKE SWITCH 

    Refer to COMPONENT INSPECTION  .

    OK or NG 

    1. OK: GO TO 8.
    2. NG: Replace ASCD brake switch.
  8. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E81, M15
    • Harness connectors M223, F53
    • Harness for open and short between ASCD clutch switch and ECM
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  9. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect stop lamp switch harness connector.
    3. Check voltage between stop lamp switch terminal 1 and ground with CONSULT-II or tester.
      Fig 10: Checking Voltage Between Stop Lamp And Ground
      G00787362Courtesy of NISSAN MOTOR CO., U.S.A.

    Voltage: Battery voltage 

    OK or NG 

    1. OK: GO TO  12 .
    2. NG: GO TO  11 .
  10. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector M17
    • 15A fuse
    • Harness connectors M15, E81
    • Harness for open or short between stop lamp switch and fuse
    1. Repair open circuit or short to ground in harness or connectors.
  11. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between stop lamp switch terminal 2 and ECM terminal 55.
      Fig 11: Checking harness continuity between Stop Lamp Switch And ECM
      G00787363Courtesy of NISSAN MOTOR CO., U.S.A.

      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: GO TO 12.
  12. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors M15, E81
    • Harness connectors M162, F55
    • Harness for open or short between stop lamp switch and ECM
    1. : 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. OK: INSPECTION END
scientia non olet · About LEMON Manuals