LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Nissan-Datsun >> 2005 >> Sentra Base, Standard >> Repair and Diagnosis >> Engine Performance >> Engine Control System (QG18DE) >> Electrical Load Signal >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

  1. INSPECTION START 

    Do you have CONSULT-II?

    Yes or No 

    • Yes : GO TO 2.
    • No : GO TO  3.
  2. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-I 

    With CONSULT-II 

    1. Turn ignition switch ON.
    2. Check "LOAD SIGNAL" in "DATA MONITOR" mode with CONSULT-II under the following conditions.
      Fig 1: CONSULT-II Display - DATA MONITOR, LOAD SIGNAL
      G02450552Courtesy of NISSAN MOTOR CO., U.S.A.
      LOAD SIGNAL CONDITIONS

      Condition LOAD SIGNAL
      Lighting switch ON at 2nd position ON
      Lighting switch OFF OFF

    OK or NG 

    • OK : GO TO  4.
    • NG : GO TO  8.
  3. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-I 

    Without CONSULT-II 

    1. Turn ignition switch ON.
    2. Check voltage between ECM terminal 84 and ground under the following conditions.
      3. Fig 2: Checking Voltage Between ECM Connector Terminal 84 And Ground
      G02450553Courtesy of NISSAN MOTOR CO., U.S.A.
    ECM TERMINAL 84 VOLTAGE REFERENCE

    Condition Voltage
    Lighting switch ON at 2nd position BATTERY VOLTAGE
    Lighting switch OFF 0V

    OK or NG 

    • OK : GO TO  5.
    • NG : GO TO  8.
  4. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-II 

    With CONSULT-II 

    1. Turn ignition switch ON.
    2. Check "HEATER FAN SW" in "DATA MONITOR" mode with CONSULT-II under the following conditions.
      3. Fig 3: CONSULT-II Display - DATA MONITOR, HEATER FAN SW
      G02450554Courtesy of NISSAN MOTOR CO., U.S.A.
    CONSULT-II FAN CONTROL INDICATION CONDITION REFERENCE

    Condition INDICATION
    FAN control switch ON in any position ON
    FAN control switch OFF OFF

    OK or NG 

    • OK : GO TO  6.
    • NG : GO TO  13.
  5. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-II 

    Without CONSULT-II 

    1. Turn ignition switch ON.
    2. Check voltage between ECM terminal 96 and ground under the following conditions.
      3. Fig 4: Checking Voltage Between ECM Connector Terminal 96 And Ground
      G02450555Courtesy of NISSAN MOTOR CO., U.S.A.
    ECM TERMINAL 96 VOLTAGE REFERENCE (FAN CONTROL)

    Condition Voltage
    FAN control switch ON in any position Approximately 0V
    FAN control switch OFF Approximately 5V

    OK or NG 

    • OK : GO TO  7.
    • NG : GO TO  13.
  6. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-III 

    With CONSULT-II 

    1. Turn ignition switch ON.
    2. Check "LOAD SIGNAL" in "DATA MONITOR" mode with CONSULT-II under the following conditions.
      3. Fig 5: CONSULT-II Display - DATA MONITOR, LOAD SIGNAL
      G02450556Courtesy of NISSAN MOTOR CO., U.S.A.
    LOAD SIGNAL CONDITIONS - REAR WINDOW DEFOGGER

    Condition LOAD SIGNAL
    Rear window defogger switch ON ON
    Rear window defogger switch OFF OFF

    OK or NG 

    • OK : INSPECTION END 
    • NG : GO TO  16.
  7. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-III 

    Without CONSULT-II 

    1. Turn ignition switch ON.
    2. Check voltage between ECM terminal 93 and ground under the following conditions.
      3. Fig 6: Checking Voltage Between ECM Connector Terminal 93 And Ground
      G02450557Courtesy of NISSAN MOTOR CO., U.S.A.
    ECM TERMINAL 93 VOLTAGE REFERENCE

    Condition Voltage
    Rear window defogger switch ON BATTERY VOLTAGE
    Rear window defogger switch OFF Approximately 0V

    OK or NG 

    • OK : INSPECTION END 
    • NG : GO TO  16.
  8. CHECK HEADLAMP FUNCTION 
    1. Start engine.
    2. Turn the lighting switch ON at 2nd position.
    3. Check that headlamps are illuminated.

    OK or NG 

  9. CHECK HEADLAMP INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Stop engine.
    2. Disconnect ECM harness connector.
    3. Disconnect lighting switch harness connector.
    4. Check harness continuity between ECM terminal 84 and lighting switch terminal 12.
      • Continuity should exist. 
      Fig 7: Checking Harness Continuity Between ECM Connector Terminal 84 And Lighting Switch Connector Terminal 12
      G02450558Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO  19.
    • NG : GO TO 12.
  10. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B)
    • Harness connectors M59, F27
    • Harness for open and short between ECM and lighting switch
      • : Repair open circuit or short to ground or short to power in harness or connectors. 
  11. CHECK HEADLAMP INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Stop engine.
    2. Disconnect ECM harness connector.
    3. Disconnect lighting switch harness connector E115.

      Disconnect daytime light control unit harness connector.

    4. Check harness continuity between ECM terminal 84 and lighting switch terminal 12, daytime light control unit terminal 6 under the following conditions.
      Fig 8: Checking Harness Continuity Between ECM Connector Terminal 84 And Lighting Switch Connector Terminal 12, Daytime Light Control Unit Terminal 6
      G02450559Courtesy of NISSAN MOTOR CO., U.S.A.
      TERMINAL CONTINUITY CONDITIONS - ECM & DAYTIME LIGHT CONTROL UNIT

      Condition Continuity
      1 Should exist
      2 Should not exist
    5. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO  19.
    • NG : GO TO 12.
  12. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E109, M20
    • Harness connectors M59, F27
    • Fuse block (J/B)
    • Diode-3
    • Harness for open and short between ECM and lighting switch
    • Harness for open and short between ECM and daytime light control unit
      • : Repair open circuit or short to ground or short to power in harness or connectors. 
  13. CHECK HEATER FAN SWITCH FUNCTION 
    1. Start engine.
    2. Turn the heater fan switch ON in any position.
    3. Check that heater fan turns properly.

    OK or NG 

  14. CHECK HEATER FAN INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Stop engine.
    2. Disconnect ECM harness connector.
    3. Disconnect fan control switch harness connector.
    4. Check harness continuity between ECM terminal 96 and fan control switch terminal 6.
      • Continuity should exist. 
    5. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO  19.
    • NG : GO TO 15.
  15. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors M59, F27
    • Harness for open and short between ECM and fan control switch
      • : Repair open circuit or short to ground or short to power in harness or connectors. 
  16. CHECK REAR WINDOW DEFOGGER FUNCTION 
    1. Start engine.
    2. Turn ON the rear window defogger switch.
    3. Check the rear windshield. Is the rear windshield heated up?

    Yes or No 

  17. CHECK REAR WINDOW DEFOGGER INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Stop engine.
    2. Disconnect ECM harness connector.
    3. Disconnect rear window defogger relay.
    4. Check harness continuity between ECM terminal 93 and rear window defogger relay terminals 5, 7.
      • Continuity should exist. 
    5. Also check harness for short to ground and short to power.

    OK or NG 

    • OK : GO TO  19.
    • NG : GO TO 18.
  18. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors B1, M14
    • Harness connectors M58, F26
    • Harness for open and short between ECM and rear window defogger relay.
      • : Repair open circuit or short to ground or short to power in harness or connectors. 
  19. CHECK INTERMITTENT INCIDENT 

    Perform "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    • : INSPECTION END 
scientia non olet · About LEMON Manuals