Diesel Engine Power Monitor (DEPM)

The DEPM strategy resides in the transmission control module (TCM) located inside of the PCM. The function of the DEPM is to monitor the engine RPM when there is no power demand from the APP sensor.

Under normal engine idle operation, the DEPM value must always be higher than the engine RPM. In the event that the RPM does increase to its calibrated idle speed value following completion of deceleration fuel shutoff due to the injectors not turning off, the DEPM disables the crank and cam output signals sent by the PCM to the fuel injection control module (FICM). The fuel injection control module monitor (FICMM) input line informs the DEPM when the injectors are turned on and when the injectors are turned off. When the FICMM line is either shorted or open, the monitor strategy assumes that the fuel injectors are always turned on and sets a DTC.