Circuit/System Description

The transmission control module (TCM) uses the serial data network to signal the engine control module (ECM) that the TCM is requesting malfunction indicator lamp (MIL) illumination. A DTC is set in the TCM and the request for MIL illumination is sent when the TCM has determined that a failure that affects emissions has occurred in the transmission control system. When the ECM receives the message from the TCM, DTC P0700 will set in the ECM.