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Home >> Infiniti >> 2012 >> QX56 RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0500 To P1424 >> DTC P1220: Fuel Pump Control Module (FPCM) >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK FPCM POWER SUPPLY CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect FPCM harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between FPCM harness connector and ground.
    FPCM Ground Voltage
    Connector terminal
    B41 10 Ground Battery voltage

    Is the inspection result normal? 

    YES: GO TO 2.

    NO: GO TO  3.

  2. DETECT MALFUNCTIONING PART

    Check the following.

    • 15 A fuse(No. 73)
    • Harness for open or short between FPCM and IPDM E/R
    • Loose or poor connection for each connector and harness

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

  3. CHECK FPCM GROUND CIRCUIT FOR OPEN AND SHORT
    1. Turn ignition switch OFF.
    2. Check the continuity between FPCM harness connector and ground.
      FPCM Ground Continuity
      Connector terminal
      B41 5 Ground Existed
    3. Also check harness for short to power.

    Is the inspection result normal? 

    YES: GO TO 4.

    NO: Repair open circuit or short to power in harness or connectors.

  4. CHECK FPCM INPUT AND OUTPUT CIRCUITS FOR OPEN AND SHORT
    1. Disconnect ECM harness connector.
    2. Check the continuity between FPCM harness connector and ECM harness connector.
      FPCM ECM Continuity
      Connector Terminal Connector terminal
      B41 8 E80 125 Existed
      9 142
    3. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO  6.

    NO: GO TO 5.

  5. DETECT MALFUNCTIONING PART

    Check the following.

    • Harness for open or short between FPCM and ECM
    • Loose or poor connection for each connector and harness

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

  6. CHECK FUEL PUMP CONTROL CIRCUIT FOR OPEN AND SHORT
    1. Disconnect fuel level sensor unit and fuel pump harness connector.
    2. Check the continuity between FPCM harness connector and fuel level sensor unit and fuel pump harness connector.
      FPCM Fuel level sensor unit and fuel pump Continuity
      Connector Terminal Connector terminal
      B41 6 C5 3 Existed
      7 1
    3. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO 7.

    NO: Repair open circuit, short to ground or short to power in harness or connectors.

  7. CHECK FPCM

    Refer to "COMPONENT INSPECTION (FPCM) ".

    Is the inspection result normal? 

    YES: GO TO 8.

    NO: Replace FPCM.

  8. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END

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