ELECTRONICALLY CONTROLLED BRAKE SYSTEM, Diagnostic DTC:C1439, C1445

DTC Code DTC Name
C1439 Steering Angle Sensor Initialization Incomplete
C1445 Vehicle Driven with Steering Angle Sensor not Initialized

DESCRIPTION

The skid control ECU acquires the steering angle sensor zero point every time the power switch is turned on (IG) and the vehicle is driven at 35 km/h (22 mph) or more for approximately 5 seconds. The ECU also stores previous zero points.

DTCs C1439 and C1445 will be cleared when the power switch is turned off (lock).

DTC Code INF Code DTC Detection Condition Trouble Area
C1439 752 After the steering angle sensor zero point calibration is cleared due to, for example, fluctuations in the power source, the steering angle sensor zero point calibration cannot be obtained for 0.048 seconds of continuous driving.

  • Steering angle sensor

  • Yaw rate and acceleration sensor (Airbag ECU assembly)

  • Brake booster with master cylinder (Skid control ECU)
C1445 753 Steering angle sensor zero point calibration cannot be obtained when the vehicle is driven without a record of steering angle sensor zero point calibration at a speed of 35 km/h (22 mph) or more for 30 seconds or more without the brake pedal being depressed.

  • Steering angle sensor

  • Yaw rate and acceleration sensor (Airbag ECU assembly)

  • Brake booster with master cylinder (Skid control ECU)

CAUTION / NOTICE / HINT

Note

Before proceeding with the inspection, explain to the customer that the output DTC is related to temporary loss of the steering angle zero calibration, such as when the power source voltage drops when the auxiliary battery is removed, and confirm that this condition occurred.

Tech Tips


  • When DTC U0073, U0123, U0124 and/or U0126 is output together with DTC C1439 and/or C1445, inspect and repair the trouble areas indicated by DTC U0073, U0123, U0124 and/or U0126 first Click here.

  • When the speed sensor or the yaw rate and acceleration sensor (airbag ECU assembly) has trouble, DTCs for the steering angle sensor may be output even when the steering angle sensor is normal. When DTCs for the speed sensor or yaw rate and acceleration sensor (airbag ECU assembly) are output together with other DTCs for the steering angle sensor, inspect and repair the speed sensor and yaw rate and acceleration sensor (airbag ECU assembly) first, and then inspect and repair the steering angle sensor.

PROCEDURE


  1. CHECK DTC


    1. Clear the DTCs Click here.

    2. Turn the power switch off (lock).

    3. Turn the power switch on (IG) again and check that no CAN communication system DTCs are output (See page for with Central Gateway ECU or Click here for without Central Gateway ECU).

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

      Result
      Result Proceed to
      DTCs (C1439 and/or C1445) are output A
      CAN communication system DTC is output (w/ Central Gateway ECU) B
      CAN communication system DTC is output (w/o Central Gateway ECU) C
      Speed sensor, yaw rate and acceleration sensor and/or steering angle sensor DTC is output D
      DTCs (C1439 and C1445) are not output E

      Tech Tips


      • When DTCs indicating CAN communication system malfunctions are output, repair the CAN communication system before repairing each corresponding sensor.

      • If there is a malfunction in the speed sensor or the yaw rate and acceleration sensor (airbag ECU assembly), an abnormal value may be output although the steering angle sensor is normal.

      • If the speed sensor and the yaw rate and acceleration sensor DTCs are output simultaneously, repair the sensors and inspect the steering angle sensor.

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


    B

    INSPECT CAN COMMUNICATION SYSTEM Click here

    C

    INSPECT CAN COMMUNICATION SYSTEM Click here

    D

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here

    E

    CHECK FOR INTERMITTENT PROBLEMS Click here

    A

  2. CHECK 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 centered correctly while driving straight ahead.

      Tech Tips

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

      OK
      The steering wheel is centered correctly.

    NG

    ADJUST FRONT WHEEL ALIGNMENT OR STEERING POSITION Click here

    OK

  3. RECONFIRM DTC


    1. Turn the power switch off (lock).

    2. Clear the DTCs Click here.

    3. Turn the power switch on (ready).

    4. Drive the vehicle and turn the steering wheel to the right and left at the speed of 35 km/h (22 mph) or more.

    5. Check if the same DTC is recorded Click here.

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

      Tech Tips

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


    A

    END

    B

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Click here