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Home >> Infiniti >> 2008 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0327 To P1145 >> DTC P0850: PNP Switch >> Diagnosis Procedure

Diagnosis Procedure

  1. CHECK DTC WITH TCM

    Refer to "OBD-II DIAGNOSTIC TROUBLE CODE (DTC) ".

    OK or NG 

    OK: GO TO 2.

    NG: Repair or replace.

  2. CHECK STARTING SYSTEM

    Turn ignition switch OFF, then turn it to START.

    Does starter motor operate? 

    Yes or No 

    Yes: GO TO 3.

    No: Refer to STARTER MOTOR .

  3. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I
    1. Turn ignition switch OFF.
    2. Disconnect A/T assembly harness connector.
    3. Disconnect combination meter harness connector.
    4. Check harness continuity between A/T assembly terminal 9 and combination meter terminal 8.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO  5.

    NG: GO TO 4.

  4. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors F14, E5
    • Harness connectors E152, M31
    • Harness for open or short between A/T assembly and combination meter

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

  5. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-II
    1. Disconnect ECM harness connector.
    2. Check harness continuity between ECM terminal 102 and combination meter terminal 7.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO  7.

    NG: GO TO 6.

  6. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness connectors M31, E152
    • Harness for open or short between ECM and combination meter

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

  7. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-III
    1. Disconnect TCM harness connector.
    2. Check harness continuity between TCM terminal 8 and A/T assembly terminal 9.

      Refer to WIRING DIAGRAM .

      Continuity should exist. 

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

    OK or NG 

    OK: GO TO 8.

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

  8. CHECK INTERMITTENT INCIDENT

    Refer to "HOW TO CHECK TERMINAL " and "INTERMITTENT INCIDENT ".

    OK or NG 

    OK: GO TO 9.

    NG: Repair or replace.

  9. REPLACE COMBINATION METER

    Refer to "REMOVAL AND INSTALLATION ".

    INSPECTION END 

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