Toyota Tacoma 2015-2018 Service Manual: Steering Angle Sensor Initialization Incomplete (C1439,C1445)

Toyota Tacoma 2015-2018 Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System(for Hydraulic Brake Booster) / Steering Angle Sensor Initialization Incomplete (C1439,C1445)

DESCRIPTION

The skid control ECU (master cylinder solenoid) acquires steering angle sensor (spiral cable with sensor sub-assembly) zero point every time the ignition switch is turned to ON and the vehicle is driven at 35 km/h (22 mph) or more for approximately 5 seconds. The ECU also stores the previous zero point.

The steering angle sensor (spiral cable with sensor sub-assembly) zero point malfunction warning will be cancelled by turning the ignition switch to off.

DTC Code	DTC Detection Condition	Trouble Area
C1439	After the steering angle sensor 0 calibration is cleared due to, for example, fluctuations in the power source, the steering angle 0 calibration cannot be obtained for 0.048 seconds of continuous driving	Steering angle sensor (spiral cable with sensor sub-assembly) Yaw rate and acceleration sensor (airbag sensor assembly) Skid control ECU (master cylinder solenoid)
C1445	Steering angle sensor 0 calibration cannot be obtained when the vehicle is driven without a record of steering angle sensor 0 calibration at a speed of 36 km/h (22 mph) or more for 30 seconds or more without the brake pedal being depressed	Steering angle sensor (spiral cable with sensor sub-assembly) Yaw rate and acceleration sensor (airbag sensor assembly) Skid control ECU (master cylinder solenoid)

CAUTION / NOTICE / HINT

NOTICE:

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 voltage drops when the battery is removed, and confirm that this condition occurred.
When replacing the skid control ECU (master cylinder solenoid), perform calibration (See page ).

HINT:

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

PROCEDURE

CHECK DTC

(a) Clear the DTCs (See page (b) Turn the ignition switch off. ).

(b) Turn the ignition switch off.

(c) Turn the ignition switch to ON again and check that no CAN communication system DTC is output (See page (d) Drive the vehicle at a speed of 35 km/h (22 mph) and turn the steering wheel ).

(d) Drive the vehicle at a speed of 35 km/h (22 mph) and turn the steering wheel to the right and left, and then check that no speed sensor and yaw rate and acceleration sensor (airbag sensor assembly) DTCs are output (See page Result Result ).

Result

Result		Proceed to
DTC is output	C1439 and/or C1445	A
	Relating to CAN communication system	B
	Relating to speed sensor or yaw rate and acceleration sensor	C
	DTC is not output	D

HINT:

If there is a malfunction in the speed sensor or the yaw rate and acceleration sensor (airbag sensor assembly), an abnormal value may be output although the steering angle sensor (spiral cable with sensor sub-assembly) is normal.
If the speed sensor and the yaw rate and acceleration sensor (airbag sensor assembly) DTCs are output simultaneously, repair the sensors and inspect the steering angle sensor (spiral cable with sensor sub-assembly).
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 calibration, such as when the power voltage drops.

GO TO COMMUNICATION SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING)

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

USE SIMULATION METHOD TO CHECK

2.	PERFORM 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.

HINT:

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

OK:

The centered position of the steering wheel is correctly set.

ADJUST FRONT WHEEL ALIGNMENT OR STEERING POSITION

3.	RECONFIRM DTC

(a) Clear the DTCs (See page (b) Turn the ignition switch off. ).

(b) Turn the ignition 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 (See page Result ).

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

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 calibration, such as when the power voltage drops.

END

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

Lost Communication with ECM (C1437)

DESCRIPTION The skid control ECU (master cylinder solenoid) receives signals from the ECM via the CAN communication system. DTC Code DTC Detection Condition Troubl ...

Steering Angle Sensor Unusual Bank Angle Detected (C1440)

DESCRIPTION If the skid control ECU (master cylinder solenoid) determines that the vehicle is being driven at a steep bank angle, the skid control ECU (master cylinder solenoid) stores DTC C1440 ...

Other materials:

Problem Symptoms Table
PROBLEM SYMPTOMS TABLE If a normal code is displayed during the DTC check but the problem still occurs, check the circuits for each problem symptom in the order given in the table below and proceed to the relevant troubleshooting page. NOTICE: When replacing the skid control ECU (master cylin ...

Coolant
Replacement REPLACEMENT PROCEDURE 1. REMOVE NO. 2 ENGINE UNDER COVER SUB-ASSEMBLY (w/ Off Road Package) 2. REMOVE NO. 1 ENGINE UNDER COVER SUB-ASSEMBLY 3. DRAIN ENGINE COOLANT CAUTION: Do not remove the radiator cap sub-assembly, cylinder block drain cock plug or radiator drain ...

Lost Communication with Cruise Control Front Distance Range Sensor (U0235)
DESCRIPTION The millimeter wave radar sensor assembly is connected to the skid control ECU (master cylinder solenoid)*1 or skid control ECU (brake actuator assembly)*2 via CAN communication. If communication with the skid control ECU (master cylinder solenoid)*1 or skid control ECU (brake act ...