Toyota Avalon (XX50) 2019-2022 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.

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.

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• 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

(a) Clear the 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.

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(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.

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

(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

(a) Turn the engine switch off.

(b) Replace the steering angle sensor.

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NEXT

(a) Clear the 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.

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