Monitor Description

The Transmission Control Module (TCM) and ECM perform 2-way communication with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine speed, required engine torque, warning indicators in the combination meter assembly, DTCs and other data. The ECM sends signals to the TCM concerning engine speed, opening angle of the throttle valve, temperature of intake air, temperature of engine coolant, engine torque and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN communication system, illuminate the MIL and store this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	DTC Output from	Priority	Note
U0101-87	Lost Communication with TCM Missing Message	All of the following conditions are met for 1.25 seconds or more (1 trip detection logic): Ignition switch ON Battery voltage is 10 V or higher No communication between engine control unit and transmission control unit	ECM to TCM circuit TCM ECM	Comes on	Engine	B	SAE: U0101