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Home >> Lexus >> 2017 >> GS 450h Base >> Repair and Diagnosis (Single Page) >> Steering >> Power 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 [09/2014 - ] >> Procedure
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DTC C15A3/63: Motor Rotation Angle Not Detected; DTC C15C5/69: Motor Rotation Signal Not Detected [09/2014 - ]: Procedure

  1. CHECK DTC 
    1. Check for DTCs (Refer to DTC CHECK / CLEAR [09/2014 - ] ).
      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:  B

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result:  C

    USE SIMULATION METHOD TO CHECK 

    (Refer to HOW TO PROCEED WITH TROUBLESHOOTING [09/2014 - 10/2015] or HOW TO PROCEED WITH TROUBLESHOOTING [10/2015 - ] )

    Result:  A

    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 [09/2014 - ] ).
    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 [09/2014 - ] ).
      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:  B

    REPLACE FRONT STEERING CONTROL ECU 

    (Refer to REMOVAL [09/2014 - ] )

    Result:  A

    See step  3

  3. INSPECT STEERING ACTUATOR ASSEMBLY 
    1. Turn the power switch off.
    2. Disconnect the VGRS ECU (front steering control ECU) connector.
      GTY525179Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    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
      N157-9 (RV) - N157-8 (RG) Always 20 to 60 Ω
      N157-3 (S1) - N157-8 (RG) Always 70 to 160 Ω
      N157-5 (S2) - N157-8 (RG) Always 60 to 150 Ω
      N157-9 (RV) - N157-3 (S1) Always 90 to 220 Ω
      N157-9 (RV) - N157-5 (S2) Always 80 to 210 Ω
      N157-3 (S1) - N157-5 (S2) Always 130 to 310 Ω
      N157-3 (S1) - Body ground Always 100 kΩ or higher
      N157-5 (S2) - Body ground Always 100 kΩ or higher
      N157-8 (RG) - Body ground Always 100 kΩ or higher
      N157-9 (RV) - Body ground Always 100 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to VGRS ECU [Front Steering Control ECU])

    Result:  OK

    OK 

    REPLACE FRONT STEERING CONTROL ECU 

    (Refer to REMOVAL [09/2014 - ] )

    Result:  NG

    NG 

    See step  4

  4. CHECK HARNESS AND CONNECTOR (FRONT STEERING CONTROL ECU - STEERING ACTUATOR ASSEMBLY) 
    1. Turn the power switch off.
    2. Disconnect the N157 VGRS ECU (front steering control ECU) connector.
    3. Disconnect the N155 steering actuator assembly connector.
    4. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      N157-3 (S1) - N155-2 (S1+) Always Below 1 Ω
      N157-5 (S2) - N155-9 (S2+) Always Below 1 Ω
      N157-8 (RG) - N155-10 (RG+) Always Below 1 Ω
      N157-9 (RV) - N155-1 (RV+) Always Below 1 Ω

    Result:  OK

    OK 

    REPLACE STEERING ACTUATOR ASSEMBLY 

    (Refer to REMOVAL [09/2014 - ] )

    Result:  NG

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR