DTC U0123-00 (VSA Control Unit)

DTC U0123-00 : CAN Communication Failure With Yaw-rate/Acceleration Sensor

NOTE

Initial Diagnosis:
The initial on-board diagnosis occurs right after the vehicle condition is turned to the ON mode, and the ABS, VSA, and brake system indicator (amber) come on, and continues until the indicator goes off.
Regular Diagnosis:
The regular on-board diagnosis begins right after the ABS, VSA, and brake system indicator (amber) go off, and it continues until the vehicle condition is turned to the OFF (LOCK) mode.
Review "How to Troubleshoot the VSA System" before doing the DTC troubleshooting procedure.
Test-drive the vehicle according to local traffic conditions and regulations. Do not test-drive on a lift unless specified.
The possible causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.

Confirmation Procedure	Basic Condition: 12 volt battery voltage 10 V Operating Condition: Start the engine. Test drive the vehicle at 7 mph (10 km/h) or more for at least 2 seconds.(Drive the vehicle on the road, not on a lift. Be careful of surrounding traffic conditions.)
Execution	Regular Diagnosis
Duration	About 2 seconds
DTC Type	1 drive cycle Brake system indicator (amber) on VSA indicator on
Fail Safe Action	Stop engine drag torque control function Stop TCS function Stop VSA function Stop agile handling assist function Stop hill start assist function Stop automatic brake hold control function Stop starting assist brake function* 1 Stop parking cooperation assist function* 2
Possible Cause	Open between the VSA modulator-control unit and the SRS unit (F-CAN A_H, F-CAN A_L lines)* 3 Open between the VSA modulator-control unit and the CAN gateway (F-CAN A_H, F-CAN A_L lines)* 4* 5 Open between the VSA modulator-control unit and the CAN gateway (F-CAN A_H, F-CAN A_L, F-CAN B_H, F-CAN B_L lines)* 4* 6 Open between the CAN gateway and the SRS unit (F-CAN A_H, F-CAN A_L lines)* 4 SRS unit internal failure VSA modulator-control unit internal failure

*1: With auto idle stop system

*2: 9-speed A/T

*3: Without ACC

*4: With ACC

*5: 2018-20

*6: 2021-23