Toyota Avalon (XX50): Steering Angle Sensor Initialization Incomplete (C1439,C1445). Steering Angle Sensor Unusual Bank Angle Detected (C1440). Invalid Data Received from Deceleration Sensor (C1442,C1443)

Toyota Avalon (XX50) 2019-2022 Service & Repair Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System(for Hv Model) / Steering Angle Sensor Initialization Incomplete (C1439,C1445). Steering Angle Sensor Unusual Bank Angle Detected (C1440). Invalid Data Received from Deceleration Sensor (C1442,C1443)

Steering Angle Sensor Initialization Incomplete (C1439,C1445)

DESCRIPTION

The skid control ECU (brake booster with master cylinder assembly) acquires the steering angle sensor zero point every time the power switch on (READY) and the vehicle is driven at 35 km/h (22 mph) or more for approximately 5 seconds. The skid control ECU (brake booster with master cylinder assembly) also stores the previous zero point.

If front wheel alignment or the steering wheel position is adjusted without disconnecting the cable from the negative (-) auxiliary battery terminal, or if the yaw rate and acceleration sensor zero point is not acquired after the adjustments have been completed, the skid control ECU (brake booster with master cylinder assembly) detects the difference between the previous zero point and newly acquired zero point and stores this DTC to indicate a poor adjustment.

Warning operation for the steering angle sensor zero point malfunction will be canceled by turning the power switch off.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C1439	Steering Angle Sensor Initialization Incomplete	752	The steering angle sensor zero point is lost (due to instability of supplied power, etc.) and cannot be acquired by the skid control ECU (brake booster with master cylinder assembly).	Steering angle sensor Yaw rate sensor (airbag ECU assembly)	Does not come on	VSC DTC
C1445	Vehicle Driven with Steering Angle Sensor not Initialized	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 15 km/h (9 mph) or more for 60 seconds or more without the brake pedal being depressed.	Steering angle sensor Yaw rate sensor (airbag ECU assembly)	Does not come on	VSC DTC

PROCEDURE

CHECK DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

Click here

(d) Turn the power switch on (READY).

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

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

HINT:

When CAN communication system DTCs 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 (airbag ECU assembly) DTCs are output simultaneously, repair these malfunctions and 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 the steering angle zero point calibration, such as when the power source voltage drops.

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

INSPECT CAN COMMUNICATION SYSTEM

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

USE SIMULATION METHOD TO CHECK

2.	CHECK STEERING ANGLE SENSOR ZERO POINT CALIBRATION

(a) Drive the vehicle straight ahead at 35 km/h (22 mph) or more for at least 5 seconds.

(b) Check that the centered position of the steering wheel is correctly set while driving straight ahead.

OK:

The steering wheel is centered correctly.

HINT:

If the front wheel alignment and steering position 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.

ADJUST FRONT WHEEL ALIGNMENT OR STEERING POSITION

3.	RECONFIRM DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

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

(e) Check if the same DTC is output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

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

END

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

Steering Angle Sensor Unusual Bank Angle Detected (C1440)

DESCRIPTION

If the skid control ECU (brake booster with master cylinder assembly) determines that the vehicle is being driven at a steep bank angle, the skid control ECU (brake booster with master cylinder assembly) stores DTC C1440 while VSC operation is temporarily disabled.

This is not a malfunction if the system and sensor circuits are normal and normal VSC operation resumes.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C1440	Steering Angle Sensor Unusual Bank Angle Detected	1157	Driving at a steep bank angle.	Yaw rate sensor (airbag ECU assembly)	Does not come on	VSC DTC

PROCEDURE

CHECK DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

(d) Perform a road test.

(e) Check if the same DTC is output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
DTC C1440 is output.	A
Yaw rate and acceleration sensor DTCs are output.	B
DTC C1440 is not output.	C

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

END (VSC TEMPORARILY DISABLED)

CLEAR DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

END

Invalid Data Received from Deceleration Sensor (C1442,C1443)

DESCRIPTION

The airbag ECU assembly has a built-in yaw rate and acceleration sensor and detects the vehicle condition using 2 circuits (GL1, GL2).

The skid control ECU (brake booster with master cylinder assembly) receives signals from the yaw rate and acceleration sensor (airbag ECU assembly) via the CAN communication system.

DTC No.	Detection Item	INF Code	DTC Detection Condition	Trouble Area	MIL	Note
C1442	Invalid Data Received from Deceleration Sensor	572	When voltage at terminal IG1 is 9.54 V or more, sensor invalid information received from acceleration sensor is ON continuously for 10 seconds or more.	Acceleration sensor (airbag ECU assembly) Acceleration sensor (airbag ECU assembly) installed improperly	Comes on	INF Code 572: SAE Code C051E ABS DTC
C1443	Invalid Data Received from Yaw Rate Sensor	715	When voltage at terminal IG1 is 9.54 V or more, sensor invalid information received from yaw rate sensor is ON continuously for 10 seconds or more.	Yaw rate sensor (airbag ECU assembly) Yaw rate sensor (airbag ECU assembly) installed improperly	Does not come on	VSC DTC

MONITOR DESCRIPTION

C051E:

The acceleration sensor (airbag ECU assembly) detects whether the sensor value is valid or invalid during self-diagnosis. When an invalid acceleration sensor (airbag ECU assembly) value is received for a certain amount of time, the skid control ECU (brake booster with master cylinder assembly) judges that the data from the acceleration sensor (airbag ECU assembly) is invalid and illuminates the MIL and stores this DTC.

MONITOR STRATEGY

Related DTCs	C051E: Acceleration sensor intermittent/erratic
Required Sensors/Components(Main)	Acceleration sensor (airbag ECU assembly)
Required Sensors/Components(Related)	Skid control ECU (brake booster with master cylinder assembly) Yaw rate and acceleration sensor (airbag ECU assembly)
Frequency of Operation	Continuous
Duration	10 seconds
MIL Operation	Immediately
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

C051E

Monitor runs whenever the following DTCs are not stored	C051C (Case 1) (Acceleration sensor range/performance) C051C (Case 2) (Acceleration sensor range/performance) C051C (Case 3) (Acceleration sensor range/performance) C051C (Case 4) (Acceleration sensor range/performance) C0520 (Case 1) (Acceleration sensor 2 out of range) C0520 (Case 2) (Acceleration sensor 1 and acceleration sensor 2 out of range) C0520 (Case 3) (Acceleration sensor internal malfunction)
All of the following conditions are met	-
Lost communication with yaw rate and acceleration sensor (airbag ECU assembly)	Not detected
IG1 voltage	Higher than 9.54 V
Acceleration sensor fail (C051C, C0520)	Not detected
Yaw rate and acceleration sensor power supply voltage (IG) invalidation/validation (CAN communication data)	"0" (Valid)

TYPICAL MALFUNCTION THRESHOLDS

C051E

Either of the following conditions is met	-
Acceleration sensor (longitudinal G) invalidation/validation (CAN communication data)	"1" (Invalid)
Acceleration sensor (lateral G) invalidation/validation (CAN communication data)	"1" (Invalid)

COMPONENT OPERATING RANGE

C051E

All of the following conditions are met	-
Lost communication with yaw rate and acceleration sensor (airbag ECU assembly)	Not detected
Acceleration sensor (longitudinal G) invalidation/validation (CAN communication data)	"0" (Valid)
Acceleration sensor (lateral G) invalidation/validation (CAN communication data)	"0" (Valid)

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the power switch on (IG).
Turn the Techstream on.
Clear the DTCs (even if no DTCs are stored, perform the clear DTC procedure).
Turn the power switch off.
Turn the power switch on (IG).
Turn the Techstream on.
Wait 10 seconds.
Enter the following menus: Chassis / ABS/VSC/TRAC / Trouble Codes.
Read the DTCs.
HINT:
- If a DTC is output, the system is malfunctioning.
- If a DTC is not output, perform the following procedure.
If the DTCs are not output, perform a universal trip and check for permanent DTCs.
Click here

HINT:
- If a permanent DTC is output, the system is malfunctioning.
- If no permanent DTCs are output, the system is normal.

CAUTION / NOTICE / HINT

NOTICE:

After replacing or reinstalling the yaw rate and acceleration sensor (airbag ECU assembly), perform yaw rate and acceleration sensor zero point calibration after clearing previously calibrated data.

Click here

PROCEDURE

CHECK DTC

(a) Clear the DTCs.

Click here

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

(d) Check if the same DTC is output.

Click here

Chassis > ABS/VSC/TRAC > Trouble Codes

Result	Proceed to
DTCs C1442 and C1443 are not output.	A
DTCs C1442 and/or C1443 are output.	B

USE SIMULATION METHOD TO CHECK

REPLACE AIRBAG ECU ASSEMBLY

Steering Angle Sensor Internal Circuit (C1433). Steering Angle Sensor Output (C1434). Malfunction in Yaw Rate Sensor (C1436)

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