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Home >> Nissan-Datsun >> 2012 >> Sentra Base, Automatic CVT Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Introduction (MR20DE) (CALIFORNIA) >> Service Information >> Power Supply And Ground Circuit >> Diagnosis Procedure

Diagnosis Procedure

  1. INSPECTION START

    Start engine.

    Is engine running? 

    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 93 and ground with CONSULT or tester.

    Voltage: Battery voltage 

    Fig 1: Checking ECM Power Supply Circuit-I
    G04925190Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO  4.

    NG: GO TO 3.

  3. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors M6, E19
    • Harness for open or short between ECM and ignition switch

    Repair open circuit or short to ground or short to power in harness or connectors.

  4. CHECK GROUND CONNECTIONS
    1. Turn ignition switch OFF.
    2. Loosen and retighten ground screws on the body.

    Refer to "GROUND INSPECTION ".

    • ←: Vehicle front
    • Body ground (1)
    Fig 2: Identifying Body Ground
    G04925191Courtesy of NISSAN NORTH AMERICA, INC.

    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 11, 107, 108, 109, 112 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 F10, E17
    • 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 terminal 3 and ground with CONSULT or tester.

    Voltage: Battery voltage 

    Fig 3: Checking ECM Power Supply Circuit-II
    G04894575Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: Go to IGNITION SIGNAL .

    NG: GO TO 8.

  8. CHECK ECM POWER SUPPLY CIRCUIT-III
    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Turn ignition switch ON and then OFF.
    3. Check voltage between ECM terminal 105 and ground with CONSULT or tester.

      Voltage: After turning ignition switch OFF, battery voltage will exist for a few seconds, then drop approximately 0 V  .

      Fig 4: Checking ECM Power Supply Circuit-III
      G04925193Courtesy of NISSAN NORTH AMERICA, INC.

      OK or NG 

      OK: GO TO  14.

      NG (Battery voltage does not exist.) >> GO TO 9.

      NG (Battery voltage exists for more than a few seconds.) >> GO TO  11.

  9. CHECK ECM POWER SUPPLY CIRCUIT-IV
    1. Turn ignition switch OFF and wait at least 10 seconds.
    2. Check voltage between ECM terminal 32 and ground with CONSULT or tester.

    Voltage: Battery voltage 

    Fig 5: Checking ECM Power Supply Circuit-IV
    G04925194Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 10.

    NG: GO TO  11.

  10. CHECK ECM POWER SUPPLY CIRCUIT-V
    1. Disconnect ECM harness connector.
    2. Disconnect IPDM E/R harness connector E43.
    3. Check harness continuity between ECM terminal 105 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  17.

    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 E43.
    3. Check harness continuity between ECM terminal 32 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  13.

    NG: GO TO 12.

  12. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors E7, F10
    • Harness for open or short between ECM and IPDM E/R

    Repair open circuit or short to ground or short to power in harness or connectors.

  13. CHECK 20 A FUSE
    1. Disconnect 20 A fuse from IPDM E/R.
    2. Check 20 A fuse.

    OK or NG 

    OK: GO TO  17.

    NG: Replace 20 A fuse.

  14. CHECK GROUND CONNECTIONS

    Loosen and retighten ground screws on the body.

    Refer to "GROUND INSPECTION ".

    • ←: Vehicle front
    • Body ground (1)
    Fig 6: Identifying Body Ground
    G04925191Courtesy of NISSAN NORTH AMERICA, INC.

    OK or NG 

    OK: GO TO 15.

    NG: Repair or replace ground connections.

  15. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminals 10, 11, 108 and ground.

      Refer to Wiring Diagram .

      Continuity should exist  .

    3. Also check harness for short to power.

    OK or NG 

    OK: GO TO  17.

    NG: GO TO 16.

  16. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors F10, E17
    • Harness for open or short between ECM and ground

    Repair open circuit or short to power in harness or connectors.

  17. CHECK INTERMITTENT INCIDENT

    Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT .

    OK or NG 

    OK: Replace IPDM E/R. Refer to INSPECTION WITH CONSULT (SELF-DIAGNOSIS) .

    NG: Repair open circuit or short to power in harness or connectors.

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