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Home >> Nissan-Datsun >> 2004 >> Sentra Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - QG18DE >> Electrical Load Signal >> Diagnostic Procedure
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Diagnostic Procedure

  1. INSPECTION START 

    Do you have CONSULT-II?

    Yes or No 

    1. Yes : GO TO 2.
    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: Load Signal Conditions Chart
      G00773437Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 2: Displaying DATA MONITOR Mode
      G00773438Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : GO TO  4.
    2. NG : GO to
  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.
      Fig 3: ECM Terminal 84 And Ground Voltage Checking Conditions
      G00773439Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 4: Checking Voltage Between ECM Terminal 84 And Ground
      G00773440Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : GO TO  5
    2. NG : GO to
  4. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-II 

    With CONSULT-II 

    1. Turn ignition switch ON.
    2. Check "LOAD SIGNAL" in "DATA MONITOR" mode with CONSULT-II under the following conditions.
      Fig 5: Load Signal Conditions Chart
      G00773441Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 6: Displaying DATA MONITOR Mode
      G00773442Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : GO TO  6.
    2. NG : GO to
  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.
      Fig 7: ECM Terminal 96 And Ground Voltage Checking Conditions
      G00773443Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 8: Checking Voltage Between ECM Terminal 96 And Ground
      G00773444Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK : GO to
    2. NG : GO to
  6. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-III 

    With CONSULT-II 

    1. Txurn ignition switch ON.
    2. Check "LOAD SIGNAL" in "DATA MONITOR" mode with CONSULT-II under the following conditions.

    OK or NG 

    1. OK : INSPECTION END.
    2. NG : GO to
      Fig 9: Load Signal Conditions Chart
      G00773445Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 10: Displaying DATA MONITOR Mode
      G00773446Courtesy of NISSAN MOTOR CO., U.S.A.
  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.
      Fig 11: ECM Terminal 93 And Ground Voltage Checking Conditions Chart
      G00774636Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 12: Checking Voltage Between ECM Terminal 93 And Ground
      G00774637Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: INSPECTION END.
    2. 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 

    1. OK (Models for USA): GO TO 9.
    2. OK (Models for Canada): GO TO  11.
    3. NG: Refer to HEADLAMP (FOR USA) or HEADLAMP (FOR CANADA) - DAYTIME RUNNING SYSTEM .
  9. CHECK HEADLAMP INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT 
    1. Stop engine.
    2. Disconnect ECM harness connector.
    3. Disconnect lighting switch harness connectors.
    4. Check harness continuity between ECM terminal 84 and lighting switch terminal 12 under the following conditions.
      Fig 13: Checking Harness Continuity Between ECM Terminal 84 And Lighting Switch Terminal 12
      G00774638Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 14: Continuity Conditions Chart
      G00774639Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  19.
    2. NG: GO TO 10.
  10. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) M1, E103
    • Harness connectors M58, F26 (Except SULEV models)
    • Harness connectors M59, F27 (SULEV models)
    • Harness for open and short between ECM and lighting switch
      1. :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 15: Checking Harness Continuity Between ECM Terminal 84 And Lighting Switch Terminal 12
      G00774640Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 16: Continuity Conditions Chart
      G00774641Courtesy of NISSAN MOTOR CO., U.S.A.
    5. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  19.
    2. NG: GO TO 12.
  12. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors E109, M20
    • Harness connectors M58, F26
    • Fuse block (J/B) M1, E103
    • Diode-3 M55
    • Harness for open and short between ECM and lighting switch
    • Harness for open and short between ECM and daytime light control unit
      1. :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 

    1. OK: GO TO 14.
    2. NG: Refer to TROUBLE DIAGNOSIS .
  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.
      1. Continuity should exist. 
    5. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  19.
    2. 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 

    1. Yes : GO TO 17.
    2. No : Refer to REAR WINDOW DEFOGGER .
  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.
      1. Continuity should exist. 
    5. Also check harness for short to ground and short to power.

    OK or NG 

    1. OK: GO TO  19.
    2. 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 .

    1. INSPECTION END 
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