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Home >> Lexus >> 2020 >> RC F Base >> Repair and Diagnosis >> Brakes >> Traction Control >> Vehicle Stability Control System - Diagnostic Codes (4 Of 5) >> Vehicle Stability Control System >> DTC C1439: Steering Angle Sensor Initialization Incomplete; DTC C1445: Vehicle Driven with Steering Angle Sensor not Initialized [11/2017 - 03/2019] >> Procedure
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DTC C1439: Steering Angle Sensor Initialization Incomplete; DTC C1445: Vehicle Driven with Steering Angle Sensor not Initialized [11/2017 - 03/2019]: Procedure

  1. CHECK DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [11/2017 - 03/2019]

      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 [11/2017 - 03/2019]

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

      Refer to DTC CHECK / CLEAR [11/2017 - 03/2019]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1439 and/or C1445 are output. A
      CAN communication system DTCs are output. B
      Speed sensor, yaw rate and acceleration sensor and/or steering angle sensor DTCs are output. C
      DTCs C1439 and C1445 are not output. D

      HINT: 

      • If a speed sensor or the yaw rate and acceleration sensor is malfunctioning, DTCs for the steering angle sensor may be stored even though the steering angle sensor is normal.
      • If speed sensor and yaw rate and acceleration sensor DTCs are output simultaneously, repair these malfunctions and then inspect the steering angle sensor.
      • If DTC C1439 and/or C1445 is not output again, the DTC may have been stored due to a temporary loss of steering angle sensor zero point calibration, such as a loss of calibration due to the power source voltage being low.

    Result: 

    INSPECT CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2017 - 03/2019] 

    Result: 

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2017 - 03/2019] 

    Result: 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2017 - 03/2019] 

    Result: 

    See step  2

  2. PERFORM STEERING ANGLE SENSOR ZERO POINT CALIBRATION 
    1. Drive the vehicle straight ahead at 35 km/h (22 mph) or more for at least 5 seconds.
    2. Check that the steering wheel is correctly centered while driving straight ahead.

      HINT: 

      If front wheel alignment and steering are adjusted as a result of an off-center steering wheel, acquire the yaw rate and acceleration sensor zero point again after the adjustments are completed.

      OK

      The steering wheel is correctly centered.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    ADJUST FRONT WHEEL ALIGNMENT OR STEERING. Refer to  ADJUSTMENT [11/2017 - 03/2019] 

    Result: 

    OK 

    See step  3

  3. RECONFIRM DTC 
    1. Turn the engine switch off.
    2. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [11/2017 - 03/2019]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    3. Turn the engine switch off.
    4. Start the engine.
    5. Drive the vehicle at a speed of 35 km/h (22 mph) or more and turn the steering wheel to the right and left.
    6. Check if the same DTC is output.

      Refer to DTC CHECK / CLEAR [11/2017 - 03/2019]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs C1439 and C1445 are not output. A
      Yaw rate and acceleration sensor and/or steering angle sensor DTCs are output. B

      HINT: 

      If DTC C1439 and/or C1445 is not output again, the DTC may have been stored due to a temporary loss of the steering angle sensor zero point calibration, such as a loss of calibration due to the power source voltage being low.

    Result: 

    END 

    Result: 

    REPLACE CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [11/2017 - 03/2019]