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Home >> Lexus >> 2021 >> LC 500 2D Coupe >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System - Diagnostic Codes (Coupe) (1 Of 4) >> Electronically Controlled Brake System >> DTC C1231/31: Steering Angle Sensor Circuit Malfunction [03/2017 - 09/2018] >> Procedure

DTC C1231/31: Steering Angle Sensor Circuit Malfunction [03/2017 - 09/2018]: Procedure

  1. CHECK DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [03/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the engine switch off.
    3. Turn the engine switch on (IG) again and check that no CAN communication system DTCs are output.

      Refer to DIAGNOSIS SYSTEM [03/2017 - 06/2019]

    4. Drive the vehicle at a speed of 35 km/h (22 mph), turn the steering wheel to the right and left, and check that no speed sensor and/or yaw rate sensor DTCs are output.

      Refer to DTC CHECK / CLEAR [03/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTC C1231/31 is output. A
      CAN communication system DTCs are output. B
      Speed sensor and/or yaw rate sensor DTCs are output. C
      DTC C1231/31 is not output. D

      HINT: 

      • When CAN communication system DTCs are output, repair the CAN communication system before repairing each corresponding sensor.
      • If there is a malfunction in a speed sensor or the yaw rate sensor, an abnormal value may be output even though the steering sensor is normal.
      • If speed sensor and yaw rate sensor DTCs are output simultaneously, repair these malfunctions and inspect the steering sensor.

    Result: 

    B 

    INSPECT CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - 09/2018] 

    Result: 

    C 

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [03/2017 - 09/2018] 

    Result: 

    D 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [03/2017 - 04/2020] 

    Result: 

    A 

    See step  2

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL) 
    1. Turn the engine switch off.
      GTY831801Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *A w/ Variable Gear Ratio Steering System
      *B w/o Variable Gear Ratio Steering System
      *a Front view of wire harness connector
      (to Steering Sensor)
    2. Remove the steering wheel and column cover.
    3. Make sure that there is no looseness at the locking part and the connecting part of the connector.
    4. Disconnect the P21*1 or P22*2 steering sensor connector.

      *1: w/o Variable Gear Ratio Steering System

      *2: w/ Variable Gear Ratio Steering System

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

      Standard Voltage

      W/O VARIABLE GEAR RATIO STEERING SYSTEM

      Tester Connection Condition Specified Condition
      P21-9 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      P21-4 (BAT) - Body ground Always 11 to 14 V
      W/ VARIABLE GEAR RATIO STEERING SYSTEM

      Tester Connection Condition Specified Condition
      P22-9 (IG1) - Body ground Engine switch on (IG) 11 to 14 V
      P22-4 (BAT) - Body ground Always 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT) 

    Result: 

    OK 

    See step  3

  3. CHECK HARNESS AND CONNECTOR (GROUND TERMINAL) 
    1. Turn the engine switch off.
      GTY795829Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *A w/ Variable Gear Ratio Steering System
      *B w/o Variable Gear Ratio Steering System
      *a Front view of wire harness connector
      (to Steering Sensor)
    2. Measure the resistance according to the value(s) in the table below.
      NOTE:

      Before measuring the resistance of the steering sensor, turn the engine switch off and leave the vehicle for 1 minute or more without operating the key or switches, or opening or closing the doors.

      Standard Resistance

      W/O VARIABLE GEAR RATIO STEERING SYSTEM

      Tester Connection Condition Specified Condition
      P21-6 (ESS) - Body ground 1 minute after engine switch off Below 1 Ω
      W/ VARIABLE GEAR RATIO STEERING SYSTEM

      Tester Connection Condition Specified Condition
      P22-6 (ESS) - Body ground 1 minute after engine switch off Below 1 Ω

      Result

      Proceed to
      OK
      NG (w/o Variable Gear Ratio Steering System)
      NG (w/ Variable Gear Ratio Steering System)

    Result: 

    OK 

    REPLACE STEERING SENSOR. Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    NG (w/o Variable Gear Ratio Steering System) 

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT) 

    Result: 

    NG (w/ Variable Gear Ratio Steering System) 

    See step  4

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

      Standard Resistance

      Tester Connection Condition Specified Condition
      P72-1 (+BO) - P22-4 (BAT) Always Below 1 Ω
      P72-1 (+BO) or P22-4 (BAT) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (VGRS ECU (FRONT STEERING CONTROL ECU)) 
    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      P72-7 (+BI) - Body ground Always 11 to 14 V
      GTY796732Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to VGRS ECU (Front Steering Control ECU))

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE VGRS ECU (FRONT STEERING CONTROL ECU). Refer to  REMOVAL [03/2017 - 05/2023] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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