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Home >> Lexus >> 2019 >> LC 500h >> Repair and Diagnosis (Single Page) >> Steering >> Manual Steering >> Variable Gear Ratio Steering System - Diagnostic Codes & Symptom Tests >> Variable Gear Ratio Steering System >> DTC C15A3/63: Motor Rotation Angle Not Detected; DTC C15C5/69: Motor Rotation Signal Not Detected [01/2017 - 09/2018] >> Procedure

DTC C15A3/63: Motor Rotation Angle Not Detected; DTC C15C5/69: Motor Rotation 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
      • DTC C15A3/63 is output as a current DTC
      • When the power switch is turned on (READY) and the steering wheel is operated, DTC C15A3/63 is output as a current DTC.
      A
      When the power switch is turned on (READY) and a wire harness is jiggled, DTC C15A3/63 is output as a current DTC. B
      DTC C15A3/63 is not output as a current DTC C

    Result: 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [01/2017 - 04/2020] 

    Result: 

    See step  2

  2. CHECK FREEZE FRAME DATA (MOTOR RESOLVER SIN PHASE OFFSET, MOTOR RESOLVER COS PHASE OFFSET) 
    1. Turn the power switch off.
    2. Connect the Techstream to the DLC3.
    3. Turn the power switch on (IG).
    4. Turn the Techstream on.
    5. Display the DTCs on the Techstream screen.

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

      Chassis > VGRS > Trouble Codes 

    6. Select DTC "C15A3/63", and check the freeze frame data for "Motor Resolver SIN Phase Offset" and "Motor Resolver COS Phase Offset".

      Refer to FREEZE FRAME DATA [01/2017 - ]

      Result

      Result Proceed to
      "Motor Resolver SIN Phase Offset" and "Motor Resolver COS Phase Offset" are 5 V or higher A
      "Motor Resolver SIN Phase Offset" and "Motor Resolver COS Phase Offset" are below 5 V B

    Result: 

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

    Result: 

    See step  3

  3. INSPECT STEERING ACTUATOR ASSEMBLY 
    1. Turn the power switch off.
    2. Disconnect the P71 VGRS ECU (front steering control ECU) connector.
      GTY828260Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to VGRS ECU [Front Steering Control ECU])
    3. Measure the resistance according to the value(s) in the table below.

      HINT: 

      Measure the resistance of the steering actuator assembly at the connector of the VGRS ECU (front steering control ECU).

      Standard Resistance

      Tester Connection Condition Specified Condition
      P71-9 (RV) - P71-8 (RG) Always 20 to 60 Ω
      P71-3 (S1) - P71-8 (RG) Always 70 to 160 Ω
      P71-5 (S2) - P71-8 (RG) Always 60 to 150 Ω
      P71-9 (RV) - P71-3 (S1) Always 90 to 220 Ω
      P71-9 (RV) - P71-5 (S2) Always 80 to 210 Ω
      P71-3 (S1) - P71-5 (S2) Always 130 to 310 Ω
      P71-3 (S1) - Body ground Always 100 kΩ or higher
      P71-5 (S2) - Body ground Always 100 kΩ or higher
      P71-8 (RG) - Body ground Always 100 kΩ or higher
      P71-9 (RV) - Body ground Always 100 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (VGRS ECU (FRONT STEERING CONTROL ECU) - STEERING ACTUATOR ASSEMBLY) 
    1. Turn the power switch off.
    2. Disconnect the P71 VGRS ECU (front steering control ECU) connector.
    3. Disconnect the P24 steering actuator assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      P71-3 (S1) - P24-2 (S1+) Always Below 1 Ω
      P71-5 (S2) - P24-9 (S2+) Always Below 1 Ω
      P71-8 (RG) - P24-10 (RG+) Always Below 1 Ω
      P71-9 (RV) - P24-1 (RV+) Always Below 1 Ω
      P71-9 (RV) - P71-8 (RG) Always 20 to 60 Ω
      P71-3 (S1) - P71-8 (RG) Always 70 to 160 Ω
      P71-5 (S2) - P71-8 (RG) Always 60 to 150 Ω
      P71-9 (RV) - P71-3 (S1) Always 90 to 220 Ω
      P71-9 (RV) - P71-5 (S2) Always 80 to 210 Ω
      P71-3 (S1) - P71-5 (S2) Always 130 to 310 Ω
      P71-3 (S1) or P24-2 (S1+) - Body ground Always 100 kΩ or higher
      P71-5 (S2) or P24-9 (S2+) - Body ground Always 100 kΩ or higher
      P71-8 (RG) or P24-10 (RG+) - Body ground Always 100 kΩ or higher
      P71-9 (RV) or P24-1 (RV+) - Body ground Always 100 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

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

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR