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Home >> Infiniti >> 2004 >> QX56 RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1208 (Transfer Case) >> Trouble Diagnosis For Symptoms >> 4WD Shift Indicator Lamp and 4LO Indicator Lamp Do Not Turn ON >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK TRANSFER CONTROL UNIT POWER SUPPLY CIRCUIT 
    1. Turn ignition switch "OFF". (Stay for at least 5 seconds.)
    2. Connect transfer control unit harness connector.
    3. Check voltage between transfer control unit harness connector terminals and ground.
      Fig 1: Transfer Control Unit Harness Connector Terminals And Ground Voltage Specifications
      G02383146Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 2: Checking Voltage Between Transfer Control Unit Harness Connector Terminals And Ground
      G02383147Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Turn ignition switch "ON". (Do not start engine.)
    5. Check voltage between transfer control unit harness connector terminals and ground.
      Fig 3: Transfer Control Unit Harness Connector Terminals And Ground Voltage Specifications
      G02383148Courtesy of NISSAN MOTOR CO., U.S.A.
      Fig 4: Checking Voltage Between Transfer Control Unit Harness Connector Terminals And Ground
      G02383149Courtesy of NISSAN MOTOR CO., U.S.A.

    OK or NG 

    1. OK: GO TO 2.
    2. NG: Check the following. If any items are damaged, repair or replace damaged parts.
      • 10A fuses No. 26 located in fuse and fusible link box and No. 59 located in the fuse and relay box. Refer to "POWER SUPPLY ROUTING CIRCUIT ".
      • 20A fuse No. 53 located in the IPDM E/R. Refer to "POWER SUPPLY ROUTING CIRCUIT ".
      • Harness for short or open between battery and transfer control unit harness connector terminals 47.
      • Harness for short or open between battery and transfer control unit harness connector terminal 29.
      • Harness for short or open between battery and transfer shut off relay harness connector E69 terminal 1 (G), and 3 (G).
      • Harness for short or open between transfer shut off relay harness connector E69 terminal 2 (SB) and transfer control unit harness connector terminal 30.
      • Harness for short or open between transfer shut off relay harness connector E69 terminal 5 (Y/R) and transfer control unit harness connector terminals 16 (Y/R) and 22 (Y/R).
      • Battery and ignition switch. Refer to "POWER SUPPLY ROUTING CIRCUIT ".
      • Transfer shut off relay. Refer to "COMPONENT INSPECTION ".
  2. CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT 
    1. Turn ignition switch "OFF". (Stay for at least 5 seconds.)
    2. Disconnect transfer control unit harness connector.
    3. Check continuity between transfer control unit harness connector E142 terminals 3 (B), 6 (B), E143 terminal 45 (B) and ground.
      1. Continuity should exist. 

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

    OK or NG 

    1. OK: GO TO 3.
    2. NG: Repair open circuit or short to ground or short to power in harness or connectors.
    Fig 5: Checking Continuity Between Transfer Control Unit Harness Connector E142 Terminals 3, 6 And E143 Terminal 45 And Ground
    G02383150Courtesy of NISSAN MOTOR CO., U.S.A.
  3. CHECK COMBINATION METER POWER SUPPLY CIRCUIT 
    1. Turn ignition switch "OFF". (Stay for at least 5 seconds.)
    2. Disconnect transfer control unit harness connector.
    3. Check voltage between combination meter harness connector terminal and ground.
      DIAGNOSTIC PROCEDURE - CONNECTOR & TERMINAL VOLTAGE

      Connector Terminal (Wire color) Voltage (Approx.)
      M24 24 (O/L) - Ground 0V
      Fig 6: Checking Voltage Between Combination Meter Harness Connector Terminal And Ground
      G02383151Courtesy of NISSAN MOTOR CO., U.S.A.
    4. Turn ignition switch "ON". (Do not start engine.)
    5. Check voltage between combination meter harness connector terminal and ground.
      DIAGNOSTIC PROCEDURE - CONNECTOR & TERMINAL VOLTAGE

      Connector Terminal (Wire color) Voltage (Approx.)
      M24 24 (O/L) - Ground Battery voltage

    OK or NG 

    1. OK: GO TO 4.
    2. NG: Check the following. If any items are damaged, repair or replace damaged parts.
    Fig 7: Checking Voltage Between Combination Meter Harness Connector Terminal And Ground
    G02383152Courtesy of NISSAN MOTOR CO., U.S.A.
  4. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND COMBINATION METER 
    1. Turn ignition switch "OFF". (Stay for at least 5 seconds.)
    2. Disconnect transfer control unit harness connector and combination meter harness connector.
    3. Check continuity between the following terminals.
      • Transfer control unit harness connector E142 terminal 2 (B/W) and combination meter harness connector M24 terminal 32 (B/W).
      • Transfer control unit harness connector E142 terminal 11 (L) and combination meter harness connector M24 terminal 31 (L).
      • Transfer control unit harness connector E142 terminal 12 (W/G) and combination meter harness connector M24 terminal 33 (W/G).
      • Transfer control unit harness connector E142 terminal 21 (BR) and combination meter harness connector M24 terminal 30 (BR).
      1. Continuity should exist. 

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

    OK or NG 

    1. OK: GO TO 5.
    2. NG: Repair or replace damaged parts.
    Fig 8: Checking Continuity Between Transfer Control Unit Harness Connector Terminals And Combination Meter Harness Connector Terminals
    G02383153Courtesy of NISSAN MOTOR CO., U.S.A.
  5. CHECK INDICATOR LAMP CIRCUIT 
    1. Connect combination meter harness connector.
    2. Disconnect transfer control unit harness connector.
    3. Turn ignition switch "ON".
    4. Ground the following terminals using suitable wiring.
      • Transfer control unit harness connector E142 terminal 2 (B/W) and ground.
      • Transfer control unit harness connector E142 terminal 11 (L) and ground.
      • Transfer control unit harness connector E142 terminal 12 (W/G) and ground.
      • Transfer control unit harness connector E142 terminal 21 (BR) and ground.

    Do indicator lamps turn on? 

    1. OK: GO TO 6.
    2. NG: Replace combination meter. Refer to "COMBINATION METER ".
    Fig 9: Grounding Transfer Control Unit Harness Connector Terminals 2, 11, 12 And 21
    G02383154Courtesy of NISSAN MOTOR CO., U.S.A.
  6. SYMPTOM CHECK 

    Check again.

    OK or NG 

    1. OK: Inspection End.
    2. NG: GO TO 7.
  7. CHECK TRANSFER CONTROL UNIT 

    Check transfer control unit input/output signal. Refer to "TRANSFER CONTROL UNIT INPUT/OUTPUT SIGNAL REFERENCE VALUES ".

    OK or NG 

    1. OK: Inspection End.
    2. NG: Check transfer control unit pin terminals for damage or loose connection with harness connector. If any items are damaged, repair or replace damaged parts.
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