DTC U0121-00: Communication Error With Electronically Controlled Brake Unit/DSC HU/Cm

U0121-00: (VCM) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	Communication error with electronically controlled brake unit/DSC HU/CM
Detection condition	The vehicle control module (VCM) cannot receive CAN signal from electronically controlled brake unit/DSC HU/CM.
Fail-safe	(See DTC TABLE [VCM] .)
Possible cause	Malfunction in CAN communication line between electronically controlled brake unit/DSC HU/CM and vehicle control module (VCM) NOTE: Perform the malfunction diagnosis according to the troubleshooting procedure for the multiplex communication system. (See MALFUNCTION DIAGNOSIS FLOW [CONTROLLER AREA NETWORK (CAN)] .)
Repeatability verification procedure	Not applicable
System wiring diagram	Not applicable