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Home › Nissan-Datsun › 2004 › Altima Base, Standard › Repair and Diagnosis › Engine Performance › Engine Control System - 2.5L › Power Supply And Ground Circuit › Diagnostic Procedure

Diagnostic Procedure

  1. INSPECTION START 

    Start engine.

    Is engine running? 

    Yes or No

    1. Yes : GO TO  8.
    2. 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

    1. OK : GO TO  4.
    2. NG : GO TO 3.
      Fig 1: Checking ECM Power Supply Circuit-I
      G02884211Courtesy of NISSAN MOTOR CO., U.S.A.
  3. DETECT MALFUNCTIONING PART 

    Check the following.

    • Fuse block (J/B) connector M4
    • 10A fuse
    • Harness connectors M71, F59
    • Harness for open or short between ECM and fuse
    1. : Repair harness or connectors.
  4. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body. Refer to "GROUND INSPECTION ".
      Fig 2: Checking Ground Connections
      G02884212Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK : GO TO 5.
    2. NG : Repair or replace ground connections.
  5. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between ECM terminals 1, 115, 116 and body ground. Refer to Wiring Diagram .

      Continuity should exist. 

    4. Also check harness for short to power.

    OK or NG

    1. OK : GO TO  7.
    2. NG : GO TO 6.
  6. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors F58, M70
    • Harness for open or short between ECM and ground
    1. : 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 terminal 17 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    1. OK : Go to "IGNITION SIGNAL ".
    2. NG : GO TO 8.
      Fig 3: Checking ECM Power Supply Circuit-II
      G02884213Courtesy of NISSAN MOTOR CO., U.S.A.
  8. CHECK ECM POWER SUPPLY CIRCUIT-III 
    1. Turn ignition switch OFF and wait at least 10 seconds.
    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. 

    OK or NG

    1. OK : GO TO  15.
    2. NG : (Battery voltage does not exist.): GO TO 9.
    3. NG : (Battery voltage exists for more than a few seconds.): GO TO  18.
      Fig 4: Checking ECM Power Supply Circuit-III
      G02884214Courtesy of NISSAN MOTOR CO., U.S.A.
  9. CHECK ECM POWER SUPPLY CIRCUIT-IV 
    1. Turn ignition switch OFF.
    2. Check voltage between ECM terminal 111 and ground with CONSULT-II or tester.

      Voltage: Battery voltage 

    OK or NG

    1. OK : GO TO 10.
    2. NG : GO TO  12.
      Fig 5: Checking ECM Power Supply Circuit-IV
      G02884215Courtesy 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 E122.
    3. Check harness continuity between ECM terminals 119, 120 and IPDM E/R terminal 18. Refer to Wiring Diagram .

      Continuity should exist. 

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

    OK or NG

    1. OK : GO TO  15.
    2. NG : GO TO 11.
  11. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness or connectors E20, F32
    • Harness for open or short between ECM and IPDM E/R
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  12. CHECK ECM POWER SUPPLY CIRCUIT-VI 
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E121.
    3. Check harness continuity between ECM terminal 111 and IPDM E/R terminal 46.

      Refer to Wiring Diagram .

      Continuity should exist. 

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

    OK or NG

    1. OK : GO TO  14.
    2. NG : GO TO 13.
  13. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness or connectors E20, F32
    • Harness for open or short between ECM and IPDM E/R
    1. : Repair open circuit or short to ground or short to power in harness or connectors.
  14. CHECK 15A FUSE 
    1. Disconnect 15A fuse from IPDM E/R.
    2. Check 15A fuse.

    OK or NG

    1. OK : GO TO  18.
    2. NG : Replace 15A fuse.
  15. CHECK GROUND CONNECTIONS 
    1. Turn ignition switch OFF.
    2. Loosen and retighten three ground screws on the body. Refer to "GROUND INSPECTION ".
      Fig 6: Checking Ground Connections
      G02884216Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG

    1. OK : GO TO 16.
    2. NG : Repair or replace ground connections.
  16. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness continuity between ECM terminals 1, 115, 116 and ground.

      Refer to Wiring Diagram .

      Continuity should exist. 

    4. Also check harness for short to power.

    OK or NG

    1. OK : GO TO  18.
    2. NG : GO TO 17.
  17. DETECT MALFUNCTIONING PART 

    Check the following.

    • Harness connectors F58, M70
    • Harness for open or short between ECM and ground
    1. : Repair open circuit or short to power in harness or connectors.
  18. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ".

    OK or NG

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