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Home >> Nissan-Datsun >> 2005 >> Pathfinder LE, 4WD >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> Power Supply And Ground Circuit >> Diagnostic Procedure

Diagnostic Procedure

  1. INSPECTION START 

    Start engine.

    Is engine running? 

    Yes or No 

    • Yes: GO TO  8.
    • No: GO TO 2.
  2. CHECK ECM POWER SUPPLY CIRCUIT-I 
    1. Turn ignition switch OFF and then ON.
    2. Check voltage between ECM terminal 109 and ground with CONSULT-II or tester.
      • Voltage: Battery voltage 

    OK or NG 

    • OK: GO TO  4.
    • NG: GO TO 3.
    Fig 1: Checking Voltage Between ECM Terminal 109 And Ground
    G02431606Courtesy of NISSAN MOTOR CO., U.S.A.
  3. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors M31, E152
    • Fuse block (J/B) connector M4
    • 10A fuse
    • Harness for open or short between ECM and fuse
    • Repair harness or connectors.
  4. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body. See Fig 2. Refer to GROUND INSPECTION .
      Fig 2: Tightening Ground Screws On Body
      G02431607Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK: GO TO 5.
    • NG: Repair or replace ground connections.
  5. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I 
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminals 1, 115, 116 and ground.

      Refer to WIRING DIAGRAM .

      • Continuity should exist. 
    3. Also check harness for short to power.

    OK or NG 

    • OK: GO TO  7.
    • NG: GO TO 6.
  6. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors F32, E2
    • Harness for open or short between ECM and ground
    • Repair open circuit or short to power in harness or connectors.
  7. CHECK ECM POWER SUPPLY CIRCUIT-II 
    1. Reconnect ECM harness connector.
    2. Turn ignition switch ON.
    3. Check voltage between IPDM E/R connector E119 terminal 3 and ground with CONSULT-II or tester.
      • Voltage: Battery voltage 

    OK or NG 

    Fig 3: Checking Voltage Between IPDM E/R Connector E119 Terminal 3 And Ground
    G02431608Courtesy of NISSAN MOTOR CO., U.S.A.
  8. CHECK ECM POWER SUPPLY CIRCUIT-III 
    1. Turn ignition switch ON and then OFF.
    2. Check voltage between ECM terminals 119, 120 and ground with CONSULT-II or tester.
      • Voltage: After turning ignition switch OFF, battery voltage will exist for a few seconds, then drop approximately 0V. 
      Fig 4: Checking Voltage Between ECM Terminals 119, 120 And Ground
      G02431609Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK: GO TO  16.
    • NG (Battery voltage does not exist.): GO TO 9.
    • NG (Battery voltage exists for more than a few seconds.): GO TO  16.
  9. CHECK ECM POWER SUPPLY CIRCUIT-IV 
    1. Turn ignition switch OFF, and wait at least 10 seconds.
    2. Check voltage between ECM terminal 111 and ground with CONSULT-II or tester.
      • Voltage: Battery voltage 

    OK or NG 

    • OK: GO TO 10.
    • NG: GO TO  11.
    Fig 5: Checking Voltage Between ECM Terminal 111 And Ground
    G02431610Courtesy of NISSAN MOTOR CO., U.S.A.
  10. CHECK ECM POWER SUPPLY CIRCUIT-V 
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E119.
    3. Check harness continuity between ECM terminals 119, 120 and IPDM E/R terminal 4.

      Refer to WIRING DIAGRAM .

      • Continuity should exist. 
    4. Also check harness for short to ground and short to power.

    OK or NG 

    • OK: GO TO  13.
    • NG: Repair open circuit or short to ground or short to power in harness or connectors.
  11. CHECK ECM POWER SUPPLY CIRCUIT-VI 
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E119.
    3. Check harness continuity between ECM terminal 111 and IPDM E/R terminal 7.

      Refer to WIRING DIAGRAM .

      • Continuity should exist. 
    4. Also check harness for short to ground and short to power.

    OK or NG 

    • OK: GO TO 12.
    • NG: Repair open circuit or short to ground or short to power in harness or connectors.
  12. CHECK 20A FUSE 
    1. Disconnect 20 A fuse from IPDM E/R.
    2. Check 20A fuse.

    OK or NG 

    • OK: GO TO  13.
    • NG: Replace 20A fuse.
  13. CHECK GROUND CONNECTIONS 

    Loosen and retighten three ground screws on the body. See Fig 6. Refer to GROUND INSPECTION .

    Fig 6: Tightening Ground Screws On Body
    G02431611Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    • OK: GO TO 14.
    • NG: Repair or replace ground connections.
  14. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II 
    1. Check harness continuity between ECM terminals 1, 115, 116 and ground.

      Refer to WIRING DIAGRAM .

      • Continuity should exist. 
    2. Also check harness for short to power.

    OK or NG 

    • OK: GO TO  16.
    • NG: GO TO 15.
  15. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors F32, E2
    • Harness for open or short between ECM and ground
    • Repair open circuit or short to power in harness or connectors.
  16. CHECK INTERMITTENT INCIDENT 

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    OK or NG 

    • OK: Replace IPDM E/R.
    • NG: Repair open circuit or short to power in harness or connectors.
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