Many control units is applied to the vehicle due to vehicle to be electronic control type and these perform many controls by receiving signals from sensors. So the common use of each sensors and the need of comunizing informations became a prominent figure.

CAN comunication method is used at power train (ABS, trnasmission, engine, ECS etc) control of vehicle because it withstands eletronical external noise by spark and can high-speed comunication. Though CAN communication, ECM and TCM hold engin RPM, APS, step of trensmission, decreasing of torque in common and perform the active control.

This DTC is set when inappropriate 4WD ECM(=TCCU : Transfer Case Control Unit) is detected.If failure is detected 4WD ECM prohibits the ITM control.