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Home >> Infiniti >> 2012 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS P0500 To P1424 >> DTC P0550: PSP Sensor >> Diagnosis Procedure
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Diagnosis Procedure

  1. CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-I
    1. Turn ignition switch OFF.
    2. Disconnect power steering pressure (PSP) sensor harness connector.
    3. Turn ignition switch ON.
    4. Check the voltage between PSP sensor harness connector terminals.
    PSP sensor Voltage (Approx.)
    Connector + -
    terminal
    F35 1 3 5 V

    Is the inspection result normal? 

    YES: GO TO  6.

    NO: GO TO 2.

  2. CHECK POWER STEERING PRESSURE SENSOR POWER SUPPLY CIRCUIT-II
    1. Check the voltage between PSP sensor harness connector and the ground.
    + - Voltage (Approx.)
    PSP sensor
    Connector terminal
    F35 1 Ground 5 V

    Is inspection result normal? 

    YES: GO TO  4.

    NO: GO TO 3.

  3. CHECK SENSOR POWER SUPPLY CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check harness connector for short to power and short to ground, between the following terminals.
    ECM Sensor
    Connector Terminal Name Connector terminal
    F111 27 Low fuel pressure sensor F25 3
    Power steering pressure sensor F35 1
    Cooling fan speed sensor F39 2
    28 FRP sensor F26 1

    Is inspection result normal? 

    YES: Perform the trouble diagnosis for power supply circuit. Refer to "DIAGNOSIS PROCEDURE ".

    NO: Repair or replace error-detected parts.

  4. CHECK PSP SENSOR GROUND CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between PSP sensor harness connector and ECM harness connector.
      + - Continuity
      PSP sensor ECM
      Connector Terminal Connector terminal
      F35 3 F111 45 Existed
    4. Also check harness for short to ground and short to power.

    Is the inspection result normal? 

    YES: GO TO 5.

    NO: Repair or replace error-detected parts.

  5. CHECK ECM GROUND CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between ECM harness connector and the ground.
    + - Continuity
    ECM
    Connector terminal
    F111 10 Ground Existed
    E80 174
    175

    Is inspection result normal? 

    YES: Check intermittent incident. Refer to "INTERMITTENT INCIDENT ".

    NO: Repair or replace error-detected parts.

  6. CHECK PSP SENSOR SIGNAL CIRCUIT
    1. Turn ignition switch OFF.
    2. Disconnect ECM harness connector.
    3. Check the continuity between PSP sensor harness connector and ECM harness connector.
      + - Continuity
      PSP sensor ECM
      Connector Terminal Connector terminal
      F35 2 F111 39 Existed
    4. Also check harness for short to ground and to power.

    Is the inspection result normal? 

    YES: GO TO 7.

    NO: Repair or replace error-detected parts.

  7. CHECK PSP SENSOR

    Refer to "COMPONENT INSPECTION (POWER STEERING PRESSURE SENSOR) ".

    Is the inspection result normal? 

    YES: GO TO 8.

    NO: Replace PSP sensor.

  8. CHECK INTERMITTENT INCIDENT

    Refer to "INTERMITTENT INCIDENT ".

    : INSPECTION END

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