POWER STEERING SYSTEM, Diagnostic DTC:C1555

DTC Code DTC Name
C1555 Motor Relay Welding Failure

DESCRIPTION

The power steering ECU assembly supplies current to the power steering motor.

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Note
C1555 Motor Relay Welding Failure Motor relay circuit malfunction

  • Power steering motor (Power steering link assembly)

  • Wire harness or connector

  • Power steering ECU assembly

 EPS warning light: Comes on -

WIRING DIAGRAM

A01MT7PE04

CAUTION / NOTICE / HINT

Note


  • If the power steering ECU assembly has been replaced, perform assist map writing, rotation angle sensor initialization and torque sensor zero point calibration.

    Click here

  • If the power steering link assembly has been replaced, perform rotation angle sensor initialization and torque sensor zero point calibration.

    Click here

PROCEDURE


  1. CHECK CONNECTORS


    1. Check the connection of the power steering ECU assembly and power steering link assembly connectors.

    2. Visually inspect the terminals of the power steering ECU assembly and power steering link assembly connectors.

      Result
      Result Proceed to
      Normal A
      Connectors not properly connected B
      Power steering ECU assembly connector terminals abnormal C
      Power steering link assembly connector terminals abnormal D

    B

    CONNECT CONNECTORS PROPERLY

    C

    REPLACE POWER STEERING ECU ASSEMBLY for LHD: Click here
    REPLACE POWER STEERING ECU ASSEMBLY for RHD: Click here

    D

    REPLACE POWER STEERING LINK ASSEMBLY Click here

    A

  2. CHECK HARNESS AND CONNECTOR (POWER STEERING ECU ASSEMBLY - POWER STEERING MOTOR)


    1. Disconnect the C4 power steering ECU assembly connector.

    2. Disconnect the C1 power steering motor connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      C1-1 (W) - C4-2 (W) Always Below 1 Ω
      C1-2 (V) - C4-1 (V) Always Below 1 Ω
      C1-3 (U) - C4-3 (U) Always Below 1 Ω
      C1-1 (W) - Body ground Always 10 kΩ or higher
      C1-2 (V) - Body ground Always 10 kΩ or higher
      C1-3 (U) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. INSPECT POWER STEERING LINK ASSEMBLY (POWER STEERING MOTOR)


    1. Disconnect the C1 power steering motor connector.

    2. A01MTMQC03
      *1 Power Steering Link Assembly
      *a Area to Set Negative Probe
      *b

      Component without harness connected

      (Power Steering Motor)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      1 (W) - 3 (U) Always 0.07 to 10 Ω
      2 (V) - 1 (W) Always 0.07 to 10 Ω
      3 (U) - 2 (V) Always 0.07 to 10 Ω
      1 (W) - Power steering link housing* Always 100 kΩ or higher
      2 (V) - Power steering link housing* Always 100 kΩ or higher
      3 (U) - Power steering link housing* Always 100 kΩ or higher

      • *: Touch the negative probe to the power steering link assembly housing at the area shown in the illustration to perform the measurement.

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE POWER STEERING LINK ASSEMBLY Click here

    OK

  4. CHECK POWER STEERING LINK ASSEMBLY (CHECK FOR CRACK IN RACK BOOTS)

    Tech Tips

    If the rack boots are cracked, water may get into the power steering link assembly, resulting in a malfunction.


    1. Remove the power steering link assembly.

      Click here

    2. Clean off any dirt or foreign matter attached to the rack boots.

    3. Using SST, move the rack ends and check that there are no cracks in the rack boots.

      OK
      There are no cracks.

      Tech Tips

      Using SST, turn the pinion shaft to move the rack ends.

      SST
      09616-00011
      Result
      Proceed to
      OK
      NG

    OK

    REPLACE POWER STEERING ECU ASSEMBLY for LHD: Click here
    REPLACE POWER STEERING ECU ASSEMBLY for RHD: Click here

    NG

    REPLACE POWER STEERING LINK ASSEMBLY Click here