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Home >> Lexus >> 2021 >> LS 500 Base, RWD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (W/ Vacuum Brake Booster) - Diagnostic Codes (4 Of 4) & Symptom Tests >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster) >> DTC C1447: External System Malfunction [12/2017 - 09/2018] >> Procedure

DTC C1447: External System Malfunction [12/2017 - 09/2018]: Procedure

  1. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [12/2017 - 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 [12/2017 - 09/2018]

    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 sensor DTCs are output.

      Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      HINT: 

      • When CAN communication DTCs are output, inspect and repair the trouble areas indicated by CAN communication first.
      • If a speed sensor or the yaw rate sensor is malfunctioning, DTCs for the steering sensor may be stored even though the steering sensor is normal.
      • If speed sensor and yaw rate sensor DTCs are output simultaneously, repair these malfunctions and then inspect the steering sensor.
      • If DTC C1447 is not output again, the DTC may have been stored due to a temporary loss of steering sensor zero point calibration, such as a loss of calibration due to the power source voltage being low.

      Result

      Result Proceed to
      DTC C1447 is output. A
      CAN communication system DTCs are output. B
      Speed sensor, yaw rate sensor and/or steering sensor (spiral with sensor cable sub-assembly) DTCs are output. C
      DTCs are not output. D

    Result: 

    B 

    INSPECT CAN COMMUNICATION SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 09/2018] 

    Result: 

    C 

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [12/2017 - 09/2018] 

    Result: 

    D 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [12/2017 - 09/2018] 

    Result: 

    A 

    See step  2

  2. CHECK STEERING 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 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 

    for AWD: Refer to ADJUSTMENT [12/2017 - 09/2018]

    for 2WD: Refer to ADJUSTMENT [12/2017 - 09/2018]

    Result: 

    OK 

    See step  3

  3. RECONFIRM DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Start the engine.
    3. 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 sensor DTCs are output.

      Refer to DTC CHECK / CLEAR [12/2017 - 09/2018]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      HINT: 

      If DTC C1447 is not output again, the DTC may have been stored due to a temporary loss of the steering sensor zero point calibration, such as a loss of calibration due to the power source voltage being low.

      Result

      Result Proceed to
      DTC C1447 is output. A
      DTCs C1447 is not output. B

    Result: 

    A 

    REPLACE VGRS ECU (FRONT STEERING CONTROL ECU). Refer to  REMOVAL [12/2017 - 09/2018] 

    Result: 

    B 

    END