Monitor Description

The transmission ECU and the ECM perform two-way communications with each other via the Controller Area Network (CAN). The transmission ECU sends signals to the ECM concerning required engine rpm, required engine torques, warning indicators in the combination meter, DTCs, and other data. The ECM sends signals to the transmission ECU concerning engine rpm, opening angles of the throttle valve, temperature of intake air, temperature of engine coolant, engine torques, and other data.

If the transmission ECU cannot communicate with the ECM, the transmission ECU will conclude that there is a malfunction in the CAN system, illuminate the MIL and set a DTC.