Toyota Avalon Service & Repair Manual: Steering Angle Sensor Initialization Incomplete (C1439,C1445)

DESCRIPTION

When the vehicle is being driven in a straight line at 15 km/h (9 mph) for 1 second or more, the skid control ECU (brake actuator assembly) calculates the steering angle sensor zero point and updates the zero point if the difference between the calculated zero point and current zero point is between 10° and 15°. The ECU also stores previous zero points.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

C1439

Steering Angle Sensor Initialization Incomplete

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 115 seconds of continuous driving.

  • Steering angle sensor
  • Yaw rate and acceleration sensor (airbag sensor assembly)

C1445

Vehicle Driven with Steering Angle Sensor not Initialized

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 15 km/h (9 mph) or more for 115 seconds or more without the brake pedal being depressed.

  • Steering angle sensor
  • Yaw rate and acceleration sensor (airbag sensor assembly)

CAUTION / NOTICE / HINT

NOTICE:

Because this DTC is related to a temporary loss of steering angle zero point calibration, before proceeding with the inspection, it is useful to confirm whether the power source voltage was interrupted by an operation such as removal or disconnection of the battery.

HINT:

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

    Click here

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

PROCEDURE

1.

CHECK DTC

(a) Clear the DTCs.

Chassis > ABS/VSC/TRAC/EPB > Clear DTCs

(b) Turn the engine switch off.

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

Click here

(d) Drive the vehicle at a speed of 50 km/h (31 mph) and turn the steering wheel to the right and left and check that no speed sensor or yaw rate and acceleration sensor (airbag sensor assembly) DTCs are output.

Chassis > ABS/VSC/TRAC/EPB > Trouble Codes

Result

Proceed to

C1439 or C1445 is output

A

CAN communication system DTCs are output

B

Speed sensor and/or yaw rate and acceleration sensor (airbag sensor assembly) DTCs are output

C

Both C1439 and C1445 are not output

D

HINT:

  • If a speed sensor or the yaw rate and acceleration sensor (airbag sensor assembly) 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 (airbag sensor assembly) 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 zero point calibration, such as a loss of calibration due to the power source voltage being low.
B

INSPECT CAN COMMUNICATION SYSTEM

C

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

D

USE SIMULATION METHOD TO CHECK

A

2.

CHECK STEERING ANGLE SENSOR ZERO POINT CALIBRATION

(a) Drive the vehicle straight ahead at 15 km/h (9 mph) or more for at least 1 second.

(b) 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.

NG

ADJUST FRONT WHEEL ALIGNMENT OR STEERING

OK

3.

REPLACE STEERING ANGLE SENSOR

(a) Turn the engine switch off.

(b) Replace the steering angle sensor.

Click here

NEXT

4.

RECONFIRM DTC

(a) Clear the DTCs.

Chassis > ABS/VSC/TRAC/EPB > Clear DTCs

(b) Turn the engine switch off.

(c) Start the engine.

(d) Drive the vehicle at a speed of 50 km/h (31 mph) or more for at least 120 seconds and turn the steering wheel to the right and left.

(e) Check if the same DTC is output.

Chassis > ABS/VSC/TRAC/EPB > Trouble Codes

Result

Proceed to

Both C1439 and C1445 are not output

A

Yaw rate and acceleration sensor (airbag sensor assembly) 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 zero point calibration, such as a loss of calibration due to the power source voltage being low.

A

END

B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

    Malfunction in Yaw Rate Sensor (C1436)

    Yaw Rate Sensor Output Value Malfunction (C1448)

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