Toyota CH-R Service Manual: Control Module Communication Bus OFF (U0073,U0100,U0123,U0126,U0142)

Toyota CH-R Service Manual / Brake Control / Dynamic Control Systems / Vehicle Stability Control System / Control Module Communication Bus OFF (U0073,U0100,U0123,U0126,U0142)

DESCRIPTION

The skid control ECU (brake actuator assembly) receives signals from the ECM, steering angle sensor, yaw rate and acceleration sensor (airbag sensor assembly) and main body ECU (multiplex network body ECU) via CAN communication.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area
U0073	Control Module Communication Bus OFF	The +BS terminal voltage is between 9.6 and a 16.5 V and a bus OFF state occurs for 0.1 seconds or more.	CAN communication system
U0100	Lost Communication with ECM / PCM	The +BS terminal voltage is between 9.6 and 16.5 V, the vehicle speed is 6 km/h (4 mph) or more, and signals cannot be sent to the ECM for 2.5 seconds or more.	CAN communication system Skid control ECU (brake actuator assembly) ECM
U0123	Lost Communication with Yaw Rate Sensor Module	The +BS terminal voltage is between 9.6 and 16.5 V, the vehicle speed is 6 km/h (4 mph) or more, and signals from the yaw rate and acceleration sensor cannot be received for 1.1 seconds or more.	CAN communication system Skid control ECU (brake actuator assembly) Yaw rate and acceleration sensor (airbag sensor assembly)
U0126	Lost Communication with Steering Angle Sensor Module	The +BS terminal voltage is between 9.6 and 16.5 V, the vehicle speed is 6 km/h (4 mph) or more, and signals from the steering angle sensor cannot be received for 1.1 seconds or more.	CAN communication system Skid control ECU (brake actuator assembly) Steering angle sensor
U0142	Lost Communication with Body Control Module "B"	The +BS terminal voltage is between 9.6 and 16.5 V, data cannot be received from main body ECU (multiplex network body ECU) continuously for 2 second or more.	CAN communication system Skid control ECU (brake actuator assembly) Main body ECU (multiplex network body ECU)

CAUTION / NOTICE / HINT

NOTICE:

When replacing the skid control ECU (brake actuator assembly), perform system variant learning.

Click here

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 a DTC.

Click here

Chassis > ABS/VSC/TRAC/EPB > Data List

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	-

Chassis > ABS/VSC/TRAC/EPB > Data List

Tester Display
EFI Communication Open
Yaw Rate Open
Deceleration Open
Steering Open

Result	Proceed to
There is a constant interruption. (Error is displayed without interruption.)	A
There are no momentary interruptions.	B
There are momentary interruptions. (Error is displayed intermittently.)	C

HINT:

Perform the above inspection before disconnecting any sensors or connectors.

GO TO STEP 3

GO TO STEP 4

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

(a) Turn the ignition switch off.

(b) Check if each sensor or ECM connector is securely connected.

OK:

Each connector is securely connected.

CONNECT CONNECTOR TO EACH SENSOR OR ECM CORRECTLY

3.	RECONFIRM DTC

(a) Turn the ignition switch off.

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

for VSC system: Click here

for CAN communication system: Click here

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

HINT:

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

Result	Proceed to
DTCs are not output.	A
DTCs are output.	B
CAN communication system DTCs 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.

Click here

5.	RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs.

Click here

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

(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.

Click here

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

Click here

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

Result	Proceed to
DTCs are not output.	A
DTCs are output.	B
CAN communication system DTCs are output.	C

HINT:

The CAN communication system must be normal when performing troubleshooting for sensor DTCs (for VSC system).

END

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

INSPECT CAN COMMUNICATION SYSTEM

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