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.

B

GO TO STEP 3

C

GO TO STEP 4

A

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.

NG

CONNECT CONNECTOR TO EACH SENSOR OR ECM CORRECTLY
OK

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
A

USE SIMULATION METHOD TO CHECK

B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

C

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 or ECM.

Click here

NEXT

5.

RECONFIRM DTC

(a) Turn the ignition switch off.

(b) Clear the DTCs.

Click here

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

(c) Turn the ignition switch off.

(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).

A

END
B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

C

INSPECT CAN COMMUNICATION SYSTEM

    Open in ABS Solenoid Relay Circuit (C146E)
    DESCRIPTION The ABS solenoid relay is built into the skid control ECU in the brake actuator assembly. The ABS solenoid relay supplies power to the ABS and TRAC solenoids. The skid control ECU det ...

    Stop Light Control Relay Malfunction (C1380)
    DESCRIPTION When the dynamic radar cruise control system*1, pre-collision system*1 or brake hold control system operates, the skid control ECU outputs a stop light drive output (STPO) signal to i ...

    Other materials:

    Toyota CH-R Service Manual > Air Conditioning System(for Automatic Air Conditioning System With Top-mounted Air Conditioner Pressure Sensor): IG Power Source Circuit
    DESCRIPTION Power source voltage is supplied to the air conditioning amplifier assembly when the ignition switch is turned ON. This power is used for operating the air conditioning amplifier assembly, servo motors, etc. WIRING DIAGRAM CAUTION / NOTICE / HINT NOTICE: Inspect the fuses for ...

    Toyota CH-R Service Manual > Audio And Visual System(for Radio And Display Type): Touch Panel Switch does not Function
    CAUTION / NOTICE / HINT NOTICE: Depending on the parts that are replaced during vehicle inspection or maintenance, performing initialization, registration or calibration may be needed. Refer to Precaution for Audio and Visual System. Click here When replacing the ...

    Toyota C-HR (AX20) 2023-2025 Owner's Manual

    Toyota CH-R Owners Manual

    Toyota CH-R Service Manual

    © 2017-2025 Copyright www.tochr.net
    0.01