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Home >> Nissan-Datsun >> 2008 >> Maxima SL >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS P0448 To P0850 >> DTC P0850 PNP Switch >> Diagnostic Procedure
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Diagnostic Procedure

  1. CHECK DTC WITH TCM 

    Refer to "TROUBLE DIAGNOSIS ."

    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 "STARTING SYSTEM ."

  3. CHECK PNP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I 
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Disconnect "unified meter and A/C amp." harness connector.
    4. Check harness continuity between ECM terminal 102 and "unified meter and A/C amp." terminal 25.

      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 M71, F59
    • Harness connectors F58, M70
    • Harness for open or short between "unified meter and A/C amp." and ECM
    • >> Repair open circuit or short to ground or short to power in harness or connectors.

  5. CHECK INTERMITTENT INCIDENT 

    Refer to "TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT ."

    OK or NG 

    OK: GO TO  6.

    NG: Repair or replace.

  6. REPLACE "UNIFIED METER AND A/C AMP." 

    Refer to "SELF-DIAGNOSTIC RESULTS ."

    >> INSPECTION END