LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2023 >> QX80 Sensory, AWD >> Repair and Diagnosis >> Steering >> Steering Control Systems >> Steering Control System (Diagnostics) >> Component Parts /Circuit Diagnosis >> Power Supply And Ground Circuit (Power Steering Control Unit) >> Diagnosis Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis Procedure

  1. CHECK POWER SUPPLY (1) 
    1. Turn the ignition switch OFF.
    2. Disconnect power steering control unit harness connector.
    3. Check the voltage between power steering control unit harness connector and ground.

      Power steering control unit

      --

      Voltage (Approx.)

      Connector

      Terminal

      M108

      3

      Ground

      0 V

    4. Turn the ignition switch ON.
      CAUTION: Never start the engine.
    5. Check the voltage between power steering control unit harness connector and ground.

      Power steering control unit

      --

      Voltage

      Connector

      Terminal

      M108

      3

      Ground

      Battery voltage

    Is the inspection result normal?

    YES

    GO TO 3.

    NO

    GO TO 2.

  2. CHECK POWER SUPPLY (2) 
    1. Turn the ignition switch OFF.
    2. Check 10A fuse (#3).
    3. Disconnect fuse block (J/B) harness connector.
    4. Check the continuity between power steering control unit harness connector and fuse block (J/B) harness connector.

      Power steering control unit

      Fuse block (J/B)

      Continuity

      Connector

      Terminal

      Connector

      Terminal

      M108

      3

      M1

      2A

      Existed

    5. Check the continuity between power steering control unit harness connector and ground.

      Power steering control unit

      --

      Continuity

      Connector

      Terminal

      M108

      3

      Ground

      Not existed

    Is the inspection result normal?

    YES

    Perform trouble diagnosis for ignition power supply circuit. Refer to Wiring Diagram .

    NO

    Repair or replace damaged parts.

  3. CHECK GROUND CIRCUIT 
    1. Turn the ignition switch OFF.
    2. Check the continuity between power steering control unit harness connector and ground.

      Power steering control unit

      --

      Continuity

      Connector

      Terminal

      M108

      6

      Ground

      Existed

    Is the inspection result normal?

    YES

    GO TO 4.

    NO

    Repair or replace error-detected parts.

  4. CHECK TERMINALS AND HARNESS CONNECTORS 

    Check the power steering control unit pin terminals for damage or loose connection with harness connector.

    Is the inspection result normal?

    YES

    INSPECTION END

    NO

    Repair or replace error-detected parts.