Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diesel Engine Power Monitor (DEPM)
The DEPM strategy resides in the transmission control module (TCM) located inside of the powertrain control module (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 injector control module (FICM). The fuel injector 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.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.