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Home › Infiniti › 2002 › I35 › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P1572: ASCD Brake Switch › Diagnostic Procedure

Diagnostic Procedure

  1. If using CONSULT-II, go to next step. If not using CONSULT-II, go to step  3 .
  2. Turn ignition on. Select BRAKE SW1 in DATA MONITOR mode with CONSULT-II. On A/T models, when brake pedal is depressed or transmission is in Park or Neutral, CONSULT-II should indicate OFF. When brake pedal is released and transmission is not in Park or Neutral, CONSULT-II should indicate ON. On M/T models, when brake pedal or clutch pedal is depressed, CONSULT-II should indicate OFF. When brake pedal and clutch pedal are released, CONSULT-II should indicate ON. On all models, if operation is as specified, go to step  4 . If operation is not as specified, go to step  5 (on A/T models) or step  21 (on M/T models).
  3. Turn ignition on. Measure voltage between ground and ECM terminal No. 59 (Green/Black wire) by backprobing. See Figure and Figure . On A/T models, when brake pedal is depressed or transmission is in Park or Neutral, voltage should be about zero volts. When brake pedal is released and transmission is not in Park or Neutral, battery voltage should exist. On M/T models, when brake pedal or clutch pedal is depressed, voltage should be about zero volts. When brake pedal and clutch pedal are released, battery voltage should exist. On all models, If operation is as specified, go to next step. If operation is not as specified, go to step  5 (on A/T models) or step  21 (on M/T models).
  4. Select BRAKE SW2 in DATA MONITOR mode with CONSULT-II. Or, measure voltage between ground and ECM terminal No. 55 (Red/Green wire) by backprobing. When brake pedal is released, CONSULT-II should indicate OFF, and voltage should be about zero volts. When brake pedal is depressed, CONSULT-II should indicate ON, and battery voltage should exist. If operation is as specified, go to step  35 . If operation is not as specified, go to step  30 .
  5. Turn ignition off. Remove Park/Neutral Position (PNP) relay. See Figure . Turn ignition on. Measure voltage between ground and PNP relay harness connector terminal No. 3 (Light Green/Red wire). See Fig 1 . When brake pedal is released, battery voltage should exist. When brake pedal is depressed, about zero volts should exist. If voltage is as specified, go to step  10 . If voltage is not as specified, go to next step.
  6. Turn ignition off. Disconnect ASCD brake switch harness connector. See Fig 2 . Turn ignition on. Measure voltage between ground and ASCD brake switch harness connector terminal No. 1 (Orange wire). If battery voltage exists, go to step  8 . If battery voltage does not exist, go to next step.
  7. Check the following:
    • Check fuse No. 30 (10-amp) located in fuse block under left side of instrument panel.
    • Check for poor connection at fuse block connector E83 terminal 7H (Orange wire). See Figure .
    • Check for open or short between ASCD brake switch and fuse.

    Repair as necessary.

  8. Turn ignition off. Check continuity of Light Green/Red wire between ASCD brake switch harness connector terminal No. 2 and PNP relay harness connector terminal No. 3. Also, check circuit for short to ground and short to voltage. If problem is found, repair as necessary. If problem is not found, go to next step.
  9. Check continuity between ASCD brake switch terminals. When brake pedal is depressed, continuity should not exist. When brake pedal is released, continuity should exist. If continuity is as specified, go to next step. If continuity is not as specified, replace ASCD brake switch.
  10. Turn ignition off. Disconnect PNP switch harness connector. See Fig 3 . Turn ignition on. Measure voltage between ground and PNP switch harness connector terminal No. 1 (Green/Orange wire). See Fig 4 . If battery voltage exists, go to step  15 . If battery voltage does not exist, go to next step.
  11. Turn ignition off. Remove PNP relay. See Figure . Turn ignition on. Measure voltage between ground and PNP relay harness connector terminal No. 1 (Brown wire). See Fig 1 . If battery voltage exists, go to step  13 . If battery voltage does not exist, go to next step.
  12. Check the following:
    • Check fuse No. 20 (15-amp) located in fuse block under left side of instrument panel.
    • Check for poor connection at fuse block connector E83 terminal 8H (Brown wire). See Figure .
    • Check Gray, 6-pin joint connector No. 8 (connector E19). See Figure . Connector E19 is located in fuse and fusible link box on left side of engine compartment. See Figure or Figure .
    • Check for open or short between PNP relay and fuse.

    Repair as necessary.

  13. Turn ignition off. Check continuity of Green/Orange wire between PNP relay harness connector terminal No. 2 and PNP switch harness connector terminal No. 1. Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  15 .
  14. Check the following:
    • Check for poor connection at Gray, 8-pin connector F17 terminal No. 1 (Green/Orange wire). See Figure . Connector F17 is located on left side of engine compartment. See Figure or Figure .
    • Check for poor connection at Gray, 10-pin connector F10 terminal No. 2 (Green/Orange wire). See Figure . Connector F10 is located on left side of engine compartment. See Figure or Figure .
    • Check for open or short between PNP relay and PNP switch.

    Repair as necessary.

  15. Remove PNP relay. Using jumper wires, apply battery voltage to relay terminals No. 1 and 2. See Fig 1 . Check continuity between terminals No. 3 and 4. Continuity should not exist. Remove jumper wires. Continuity should exist. If continuity is as specified, go to next step. If continuity is not as specified, replace PNP relay.
  16. Turn ignition off. Disconnect PNP switch harness connector. Check continuity between ground and PNP switch harness connector terminal No. 2 (Black wire). Continuity should exist. Also, check circuit for short to voltage. If problem is found, go to next step. If problem is not found, go to step  18 .
  17. Check the following:
    • Check for poor connection at Gray, 10-pin connector F10 terminal No. 3 (Black wire). See Figure . Connector F10 is located on left side of engine compartment. See Figure or Figure .
    • Check for open or short between PNP switch and ground.

    Repair as necessary.

  18. Check continuity between PNP switch terminals No. 1 and 2. See Fig 5 . When transmission is in Park or Neutral, continuity should exist. When transmission in not Park or Neutral, continuity should not exist. If continuity is as specified, go to next step. If continuity is not as specified, replace PNP switch.
  19. Turn ignition off. Disconnect ECM harness connector. See Figure . Check continuity of Green/Black wire between PNP relay harness connector terminal No. 4 and ECM harness connector terminal No. 59. See Figure and Fig 1 . Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  21 .
  20. Check the following:
    • Check for poor connection at White, 18-pin connector F53 (On I35) or F55 (on Maxima) terminal No. 2 (Green/Black wire). See Figure . Connector is located near ECM. See Figure or Figure .
    • Check for poor connection at Super Multiple Junction (SMJ) connector M15 terminal 4D (Green/Black wire). See Figure . SMJ connector M15 is located under left side of instrument panel. See Figure or Figure .
    • Check for open or short between PNP relay and ECM.

    Repair as necessary.

  21. Turn ignition off. Disconnect ASCD clutch switch harness connector (connector M14). See Figure . Turn ignition on. Measure voltage between ground and ASCD clutch switch harness connector terminal No. 1 (Light Green/Red wire). When brake pedal is released, battery voltage should exist. When brake pedal is depressed, about zero volts should exist. If voltage is as specified, go to step  27 . If voltage is not as specified, go to next step.
  22. Turn ignition off. Disconnect ASCD brake switch harness connector. See Fig 2 . Turn ignition on. Measure voltage between ground and ASCD brake switch harness connector terminal No. 1 (Orange wire). If battery voltage exists, go to step  24 . If battery voltage does not exist, go to next step.
  23. Check the following:
    • Check fuse No. 30 (10-amp) located in fuse block under left side of instrument panel.
    • Check for poor connection at fuse block connector E83 terminal 7H (Orange wire). See Figure .
    • Check for open or short between ASCD brake switch and fuse.

    Repair as necessary.

  24. Turn ignition off. Disconnect ASCD clutch switch harness connector (connector M14). See Figure . Check continuity of Light Green/Red wire between ASCD clutch switch harness connector terminal No. 1 and ASCD brake switch harness connector terminal No. 2. Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  26 .
  25. Check the following:
    • Check for poor connection at Super Multiple Junction (SMJ) connector M15 terminal 4D (Light Green/Red wire). See Figure . SMJ connector M15 is located under left side of instrument panel. See Figure or Figure .
    • Check for open or short between ASCD brake switch and ASCD clutch switch.

    Repair as necessary.

  26. Check continuity between ASCD brake switch terminals. When brake pedal is depressed, continuity should not exist. When brake pedal is released, continuity should exist. If continuity is as specified, go to next step. If continuity is not as specified, replace ASCD brake switch.
  27. Turn ignition off. Check continuity of Green/Black wire between ASCD clutch switch harness connector terminal No. 2 and ECM harness connector terminal No. 59. Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  29 .
  28. Check the following:
    • Check for poor connection at White, 18-pin connector F55 terminal No. 2 (Green/Black wire). See Figure . Connector F55 is located near ECM. See Figure .
    • Check for open or short between ASCD clutch switch and ECM.

    Repair as necessary.

  29. Check continuity between ASCD clutch switch terminals. When clutch pedal is depressed, continuity should not exist. When clutch pedal is released, continuity should exist. If continuity is as specified, go to next step. If continuity is not as specified, replace ASCD clutch switch.
  30. Turn ignition off. Disconnect stop lamp switch harness connector. See Fig 2 . Measure voltage between ground and stop lamp switch harness connector terminal No. 1 (Orange wire). If battery voltage exists, go to step  32 . If battery voltage does not exist, go to next step.
  31. Check the following:
    • Check fuse No. 20 (15-amp) located in fuse block under left side of instrument panel.
    • Check for poor connection at fuse block connector M17 terminal 11K (Orange wire). See Figure .
    • Check for poor connection at Super Multiple Junction (SMJ) connector M15 terminal 4A (Orange wire). See Figure . SMJ connector M15 is located under left side of instrument panel. See Figure or Figure .
    • Check for open or short between stop lamp switch and fuse.

    Repair as necessary.

  32. Disconnect ECM harness connector. Check continuity of Red/Green wire between stop lamp switch harness connector terminal No. 2 and ECM harness connector terminal No. 55. Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  34 .
  33. Check the following:
    • Check for poor connection at White, 18-pin connector F53 (On I35) or F55 (on Maxima) terminal No. 1 (Red/Green wire). See Figure . Connector is located near ECM. See Figure or Figure .
    • Check for poor connection at Super Multiple Junction (SMJ) connector M15 terminal 2A (Red/Green wire). See Figure . SMJ connector M15 is located under left side of instrument panel. See Figure or Figure .
    • Check for open or short between stop lamp switch and ECM.

    Repair as necessary.

  34. Check continuity between stop lamp switch terminals. When brake pedal is depressed, continuity should exist. When brake pedal is released, continuity should not exist. If continuity is as specified, go to next step. If continuity is not as specified, replace stop lamp switch.
  35. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Testing PNP Relay
G00103825Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Locating ASCD Brake Switch & Stop Lamp Switch
G00103826Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 3: Locating PNP Switch Harness Connector
G00103828Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 4: Identifying PNP Switch Harness Connector Terminals
G00103827Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 5: Testing PNP Switch
G00103829Courtesy of NISSAN MOTOR CO., U.S.A.
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