CHECK ENGINE indicator lamp

Fig 1: Identifying Communication Diagram - CHECK ENGINE Indicator Lamp

Courtesy of SAAB-SCANIA OF AMERICA, INC.

Fig 2: Identifying Communication Circuit Diagram - CHECK ENGINE Indicator Lamp

Courtesy of SAAB-SCANIA OF AMERICA, INC.

The CHECK ENGINE lamp (MIL) warns the driver when a fault occurs in the engine management system.

The lamp is powered from the main instrument unit and is grounded by the main instrument unit control module. Trionic T7 sends continuous bus information CHECK ENGINE, unit ON/OFF.

With CHECK ENGINE ON, the control module grounds the output for the lamp to turn it on.

TCM will turn on the CHECK ENGINE lamp on certain markets.

With the ignition ON the lamp remains on until the engine starts. If there are no faults the lamp will go out.

If Trionic T7 changes the status of the message to CHECK ENGINE OFF, the lamp will go out.