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Home >> Infiniti >> 2024 >> QX55 Essential >> Repair and Diagnosis >> Steering >> Steering Control Systems >> Steering Control System (Electric Power Steering) (DTC/Circuit Diagnosis) >> DTC/Circuit Diagnosis >> U140E Chassis Control Module >> DTC Diagnosis Procedure
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DTC Diagnosis Procedure

  1. PERFORM CHASSIS CONTROL MODULE SELF-DIAGNOSIS 
    1. SYMBOL CONSULT
      1. Ignition switch ON.
      2. Select "Self Diagnostic Result" mode of "CHASSIS CONTROL". Refer to CONSULT Function .

    Is any DTC detected?

    YES>>

    Check the DTC. Refer to DTC Index .

    NO>>

    GO TO 2.

  2. CHECK CONNECTOR AND TERMINAL 
      1. Ignition switch OFF.
      2. Disconnect chassis control module connector.
      3. Disconnect EPS control unit connector.
      4. Check the connector for disconnection or looseness.
      5. Check the pin terminals for damage or loose connection with harness connector.

    Is the inspection result normal?

    YES>>

    GO TO 3.

    NO>>

    Repair or replace harness, connector, or terminal, securely lock the connector.

  3. PERFORM SELF-DIAGNOSIS 
    1. SYMBOL CONSULT
      1. Connect chassis control module connector.
      2. Connect EPS control unit connector.
      3. Ignition switch ON.
      4. Erase "Self Diagnostic Result" of "EPS/DAST 3".
      5. Ignition switch OFF and wait for at least 10 seconds.
      6. Ignition switch ON.
      7. Select "Self Diagnostic Result" mode of "EPS/DAST 3".

    Is DTC "U140E" detected?

    YES>>

    EPS control unit is malfunctioning. Replace steering gear assembly. Refer to Removal and Installation .

    NO>>

    Check pin terminal and connection of each harness connector for malfunctioning conditions.