DTC C1203: ECM Communication Circuit Malfunction [08/2015 - 08/2019]: Description

This circuit is used to send TRAC and VSC control information from the skid control ECU (brake actuator assembly) to the ECM, and engine control information from the ECM to the skid control ECU (brake actuator assembly) via CAN communication.

DTC No.	DTC Detection Condition	Trouble Area
C1203	Either of the following is detected: Engine model information sent from the ECM does not match the information stored in the skid control ECU. No system information stored in the skid control ECU. Incorrect installation of the skid control ECU or ECM.	ECM malfunction or ECM with incorrect part number installed Skid control ECU (Brake actuator assembly)