LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Nissan-Datsun >> 2004 >> Altima Base, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control System - 2.5L >> 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 "BRAKE SW1" indication under the following conditions.

      M/T models 

      BRAKE SW1 INDICATION CONDITIONS (M/T MODELS)

      CONDITION INDICATION
      When clutch pedal or brake pedal is depressed OFF
      When clutch pedal and brake pedal are fully released ON

      A/T models 

      BRAKE SW1 INDICATION CONDITIONS (A/T MODELS)

      CONDITION INDICATION
      When brake pedal is depressed OFF
      When brake pedal is fully released ON
      Fig 1: Displaying BRAKE SW1 In DATA MONITOR Mode
      G02885001Courtesy 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.

      M/T models 

      VOLTAGE CHECKING CONDITIONS (M/T MODELS)

      CONDITION VOLTAGE
      When clutch pedal or brake pedal is depressed Approximately 0V
      When clutch pedal and brake pedal are fully released Battery voltage

      A/T models 

      VOLTAGE CHECKING CONDITIONS (A/T MODELS)

      CONDITION VOLTAGE
      When brake pedal is depressed Approximately 0V
      When brake pedal is fully released Battery voltage
      Fig 2: Checking Voltage Between ECM Terminal 108 & Ground
      G02885002Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK : GO TO 2.
    2. NG (M/T models) : GO TO  3.
    3. NG (A/T models) : GO TO  8.
  2. CHECK OVERALL FUNCTION-II 

    With CONSULT-II 

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

    BRAKE SW2 INDICATION CONDITION

    CONDITION INDICATION
    When brake pedal is released OFF
    When brake pedal is depressed ON
    Fig 3: Displaying BRAKE SW2 In DATA MONITOR Mode
    G02885003Courtesy of NISSAN MOTOR CO., U.S.A.

    Without CONSULT-II 

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

    VOLTAGE CHECKING CONDITIONS

    CONDITION VOLTAGE
    When brake pedal is released Approximately 0V
    When brake pedal is depressed Battery voltage
    Fig 4: Checking Voltage Between ECM Terminal 101 & Ground
    G02885004Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK : INSPECTION END 
    2. NG : GO TO  13.
  3. CHECK ASCD CLUTCH SWITCH CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ASCD brake switch harness connector.
    3. Turn ignition switch ON.
      Fig 5: Identifying ASCD Brake Switch
      G02885005Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between ASCD brake switch terminal 1 and ground under the following conditions with CONSULT-II or tester.
      ASCD BRAKE SWITCH TERMINAL VOLTAGE CHECKING CONDITIONS

      CONDITION VOLTAGE
      When clutch pedal is released Battery voltage
      When clutch pedal is depressed Approx. 0V

    OK or NG

    1. OK : GO TO  10.
    2. NG : GO TO 4.
      Fig 6: Checking Voltage Between ASCD Brake Switch Terminal 1 & Ground
      G02885006Courtesy of NISSAN MOTOR CO., U.S.A.
  4. CHECK ASCD CLUTCH SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ASCD clutch switch harness connector.
    3. Turn ignition switch ON.
      Fig 7: Disconnecting ASCD Clutch Switch Harness Connector
      G02885007Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between ASCD clutch switch terminal 1 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    1. OK : GO TO  6.
    2. NG : GO TO 5.
      Fig 8: Checking Voltage Between ASCD Clutch Switch Terminal 1 & Ground
      G02885008Courtesy of NISSAN MOTOR CO., U.S.A.
  5. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector E30
    • 10A fuse
    • Harness for open or short between ASCD clutch switch and fuse
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  6. CHECK ASCD CLUTCH SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Turn ignition switch OFF.
    2. Check harness continuity between ASCD clutch switch terminal 2 and ASCD brake switch terminal 1. Refer to Wiring Diagram .

      Continuity should exist. 

    3. 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.
  7. CHECK ASCD CLUTCH SWITCH 

    Refer to "COMPONENT INSPECTION "

    OK or NG

    1. OK : GO TO  18.
    2. NG : Replace ASCD clutch switch.
  8. CHECK ASCD BRAKE SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect ASCD brake switch harness connector.
    3. Turn ignition switch ON.
      Fig 9: Identifying ASCD Brake Switch
      G02885009Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Check voltage between ASCD brake switch terminal 1 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    1. OK : GO TO  10.
    2. NG : GO TO 9.
      Fig 10: Checking Voltage Between ASCD Brake Switch Terminal 1 & Ground
      G02885010Courtesy of NISSAN MOTOR CO., U.S.A.
  9. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector E30
    • 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.
  10. CHECK ASCD BRAKE SWITCH 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 ASCD brake switch terminal 2. Refer to Wiring Diagram .

      Continuity should exist. 

    4. Also check harness for short to ground or short to power.

    OK or NG

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

    Check the following.

    • Harness connectors E21, F34
    • Harness for open or short between ECM and ASCD brake switch
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  12. CHECK ASCD BRAKE SWITCH 

    Refer to "COMPONENT INSPECTION "

    OK or NG

    1. OK : GO TO  18.
    2. NG : Replace ASCD brake switch.
  13. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT 
    1. Turn ignition switch OFF.
    2. Disconnect stop lamp switch harness connector.
      Fig 11: Identifying Stop Lamp Switch
      G02885011Courtesy of NISSAN MOTOR CO., U.S.A.
    3. Check voltage between stop lamp switch terminal 1 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    1. OK : GO TO  15.
    2. NG : GO TO 14.
      Fig 12: Checking Voltage Between Stop Lamp Switch Terminal 1 & Ground
      G02885012Courtesy of NISSAN MOTOR CO., U.S.A.
  14. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector E30
    • 10A fuse
    • Harness for open or short between stop lamp switch and fuse
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  15. 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 2. Refer to Wiring Diagram .

      Continuity should exist. 

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

    OK or NG

    1. OK : GO TO  17.
    2. NG : GO TO 16.
  16. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E28, M7
    • Harness connectors M71, F59
    • Harness for open or short between ECM and stop lamp switch
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  17. CHECK STOP LAMP SWITCH 

    Refer to "COMPONENT INSPECTION "

    OK or NG

    1. OK : GO TO 18.
    2. NG : Replace stop lamp switch.
  18. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    1. >> INSPECTION END 
scientia non olet · About LEMON Manuals