BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: U0073,U0100,U0124,U0126; Control Module Communication Bus OFF; 2018 - 2020 MY Sienna [11/2017

Last Modified: 04-05-2023	6.11:8.1.0	Doc ID: RM1000000018KF5
Model Year Start: 2018	Model: Sienna	Prod Date Range: [11/2017 - ]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: U0073,U0100,U0124,U0126; Control Module Communication Bus OFF; 2018 - 2020 MY Sienna [11/2017 - ]

DTC

U0073

Control Module Communication Bus OFF

DTC

U0100

Lost Communication with ECM / PCM

DTC

U0124

Lost Communication with Lateral Acceleration Sensor Module

DTC

U0126

Lost Communication with Steering Angle Sensor Module

DESCRIPTION

The skid control ECU (brake actuator assembly) receives signals from the ECM, steering angle sensor (spiral cable with sensor sub-assembly) and yaw rate and acceleration sensor (airbag sensor assembly) via the CAN communication system.

DTC No.	DTC Detection Condition	Trouble Area
U0073	Any of the following is detected: A bus OFF state occurs once or more within 0.1 seconds, 10 times in succession. (Sent signals cannot be received.) When the +BS terminal voltage is between 10 and 17.4 V, a delay in receiving data from the yaw rate sensor and steering angle sensor continues for 1 second or more. When the +BS terminal voltage is between 10 and 17.4 V, the following occurs 10 times in succession within 60 seconds. The condition that a delay in receiving data from the yaw rate sensor and steering angle sensor occurs more than once within 5 seconds.	CAN communication system
U0100	When the +BS terminal voltage is between 10 and 17.4 V, and the vehicle speed is 15 km/h (9 mph) or more, data cannot be received from the ECM for 2 seconds or more.	CAN communication system Skid control ECU (brake actuator assembly) ECM
U0124	Any of the following is detected: When the +BS terminal voltage is between 10 and 17.4 V, and the vehicle speed is 7 km/h or more, data from the acceleration sensor cannot be received for 1 second or more. When the +BS terminal voltage is between 10 and 17.4 V, the following occurs 10 times in succession within 60 seconds. The condition that data from the acceleration sensor cannot be received occurs once or more within 5 seconds.	CAN communication system Skid control ECU (brake actuator assembly) Acceleration sensor (yaw rate and acceleration sensor)
U0126	Any of the following is detected: When the +BS terminal voltage is between 10 and 17.4 V, data from the steering angle sensor cannot be received for 1 second or more. When the +BS terminal voltage is between 10 and 17.4 V, the following occurs 10 times in succession. The condition that data from the steering angle sensor cannot be received occurs once or more within 5 seconds.	CAN communication system Skid control ECU (brake actuator assembly) Steering angle sensor (Spiral cable with sensor sub-assembly)

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

(a) Using the Techstream, check for any momentary interruption in the wire harness and connector corresponding to the DTC (See page ).

ABS/VSC/TRAC

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
EFI Communication Open	ECM communication open detection / Error or Normal	Error: Momentary interruption Normal: Normal	-
Yaw Rate Open	Yaw rate sensor open detection / Error or Normal	Error: Momentary interruption Normal: Normal	-
Deceleration Open	Acceleration sensor open detection / Error or Normal	Error: Momentary interruption Normal: Normal	-
Steering Open	Steering angle sensor open detection / Error or Normal	Error: Momentary interruption Normal: Normal	-

Result	Proceed to
There is a constant interruption.	A
There are no momentary interruptions.	B
There are momentary interruptions.	C

HINT:

Perform the above inspection before removing the sensor and connector.

GO TO STEP 3

GO TO STEP 4

2.	CHECK IF EACH CONNECTOR IS SECURELY CONNECTED (ECM, SENSOR, AIRBAG SENSOR ASSEMBLY)

(a) Turn the ignition switch off.

(b) Check if each sensor, ECM and yaw rate and acceleration sensor (airbag sensor assembly) connector is securely connected.

OK:

Each connector is securely connected.

CONNECT CONNECTOR TO EACH SENSOR, ECM, AIRBAG SENSOR ASSEMBLY CORRECTLY

3.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Record the output DTCs (for VSC system and/or CAN communication system) (See page for VSC system, or for CAN communication system.

HINT:

If the CAN communication system DTC and the relevant sensor DTCs are output simultaneously, troubleshoot the relevant sensor DTCs (for VSC system) after the CAN communication system returns to normal.

Result	Proceed to
DTCs are not output.	A
DTCs (relating to VSC system) are output.	B
DTCs (relating to CAN communication system) are output.	C

USE SIMULATION METHOD TO CHECK

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

INSPECT CAN COMMUNICATION SYSTEM

4.	REPAIR OR REPLACE HARNESS OR CONNECTOR

(a) Turn the ignition switch off.

(b) Repair or replace the harness or connector.

(c) Check for any momentary interruptions between the skid control ECU (brake actuator assembly) and each sensor, ECM and yaw rate and acceleration sensor (airbag sensor assembly) (See page ).

5.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs (See page ).

(d) Start the engine.

(e) Drive the vehicle at a speed of 15 km/h (9 mph) or more and turn the steering wheel to the right and left.

(f) Check that no CAN communication system DTCs are output (See page ).

(g) If VSC system DTCs are output, record them (See page ).

Result	Proceed to
DTCs are not output.	A
DTCs (relating to VSC system) are output.	B
DTCs (relating to CAN communication system) are output.	C

HINT:

The CAN communication system must be normal when repairing each sensor DTC (for VSC system).

END

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

INSPECT CAN COMMUNICATION SYSTEM