lisischeff

driving home from NH yesterday with a full fresh tank of diesel from the day before..entering highway on ramp I had maybe 1/2 power..60ish up hills..80 on the flat/straights..mashing accelerator pedal did not initiate downshifts.. no chk eng lights or messages...did not want to turn off and recycle because the whole family was in the car...drove 100ish miles came home and went out a couple hours later ..BINGO..back to full power, no chk eng, no msg's..even today all is well...clogged fuel filters on my previous 220D,240D, or 300TDT, didn't magically fix themselves

dgiturbo

Get the codes dealer scanned and verify the exact problem. Even though now "all is well," you may have just gotten a warning of things to come. Limp home mode on these is usually caused by tranny issues or swirl motor. Next time may leave you stuck.

alx

Your fuel filter is most likely the culprit.

If in doubt- keep the truck in say 2nd gear and mash the throttle. If you don't go over say 3500 rpms- it is most likely the fuel filter. 20k miles between changes is optimistic - at least in my opinion.

lisischeff

so a buddy helped me read CODE 2078-8 pressure differential sensor..? what now?

alx

It is either your pressure diff sensor going bad or your dpf (diesel particulate filter) which is less likely.

It could have been a burn- off cycle gone bad (the diesels do that every so often to clean the components of the emissions system).

If I was you I would wait to happen again and if it does- replace the pressure diff sensor which is located in the tranny tunnel close to the exhaust.

Fourdiesel

I had the differential pressure sensor replaced (sensor read off scale high) on mine a short time ago. I don't know what code number it threw but it DID set a check engine light. The sensor monitors the differential across the DPF filter. After the sensor was replaced, the CEL came back. The dealer ended up replacing the entire catalytic DPF converter ($3200) under the emissions warranty - up to 80K miles. The light has since stayed off.
The sensor ($120) was easy to replace. A couple of rubber tubes, two bolts, and tube clamps. It is up in the tunnel just above the front of the DPF and can be identified by the two rubber tubes going from the exhaust system to the small plastic sensor housing.
I looked inside the DPF on mine after it came off and it looked a little black but it did NOT look to be plugged - the holes passing the exhaust were open.

lisischeff

Thank You all for your help...so far so good...full power and no warning lights...big trip comming this weekend good for about 800 miles...ill make sure to blow it out real good