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Home >> Lexus >> 2018 >> LC 500h >> Repair and Diagnosis (Single Page) >> Steering >> Power Steering >> Variable Gear Ratio Steering System - Diagnostic Codes & Symptom Tests >> Variable Gear Ratio Steering System >> DTC C1595/55: Lost Communication with Steering Angle Sensor Module(SIL); DTC C15C4/68: Steering Signal Not Detected [01/2017 - 09/2018] >> Procedure
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DTC C1595/55: Lost Communication with Steering Angle Sensor Module(SIL); DTC C15C4/68: Steering Signal Not Detected [01/2017 - 09/2018]: Procedure

  1. CHECK DTC 
    1. Check for DTCs.

      Refer to DTC CHECK / CLEAR [01/2017 - 09/2018]

      Chassis > VGRS > Trouble Codes 

      Result

      Result Proceed to
      DTCs C15C1/74, C15C2/74 and U0126/56 are not output A
      DTCs C15C1/74, C15C2/74 and U0126/56 are output B

    Result: 

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [01/2017 - 09/2018] 

    Result: 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (VGRS ECU (FRONT STEERING CONTROL ECU) - STEERING SENSOR) 
    1. Turn the power switch off.
    2. Disconnect the P72 VGRS ECU (front steering control ECU) connector.
    3. Disconnect the P22 steering sensor connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P72-5 (SS1-) - P22-10 (SS2-) Always Below 1 Ω
      P72-6 (SS1+) - P22-5 (SS2+) Always Below 1 Ω
      P72-5 (SS1-) or P22-10 (SS2-) - Body ground Always 100 kΩ or higher
      P72-6 (SS1+) or P22-5 (SS2+) - Body ground Always 100 kΩ or higher
      P72-5 (SS1-) - P72-6 (SS1+) Always 1000 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  3

  3. CHECK STEERING SENSOR 
    1. Reconnect the P72 VGRS ECU (front steering control ECU) connector.
      GTY823212Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (VGRS ECU [Front Steering Control ECU])
    2. Reconnect the P22 steering sensor connector.
    3. Turn the power switch on (READY).
    4. Measure the voltage according to the value(s) in the table below.

      HINT: 

      With the connector connected to the VGRS ECU (front steering control ECU), measure the voltage from the rear of the connector.

      Standard Voltage

      Tester Connection Condition Specified Condition
      P72-5 (SS1-) - Body ground Steering wheel rotated slowly Pulse waveform that alternates between 0 and 5 V is output
      P72-6 (SS1+) - Body ground

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE VGRS ECU (FRONT STEERING CONTROL ECU). Refer to  REMOVAL [01/2017 - 05/2023] 

    Result: 

    NG 

    REPLACE STEERING SENSOR. Refer to  REMOVAL [01/2017 - 05/2023]