Faulty Engine Control Module (ECM)
Engine Control Module harness is open or shorted
Engine Control Module circuit poor electrical connection
Engine Light ON (or Service Engine Soon Warning Light)
Devices connected to the serial data circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the devices. The devices have prerecorded information about what messages are needed to be exchanged on the serial data circuits, for each virtual network. The messages are supervised and also, some periodic messages are used by the receiver device as an availability indication of the transmitter device. Each message contains the identification number of the transmitter device. The Diagnostic Trouble Code (DTC) will set if a supervised periodic message that includes the transmitter device availability has not been received.