Mk 4 Mondeo 2l niggling "Service Oil" and running issue.

[JenningsCar]

I don't know whether anyone can help point me in the right direction on this one...I've got an 09 mk4 Mondeo with the 2litre diesel engine, which I've owned for maybe three years now. For maybe the last 9 months it's been going through phases of displaying the "Service Oil" warning, irrespective of how new the oil and filters are. Sometimes this progresses to the amber "Engine Malfunction" warning. Also the car feels "confused" in its running from time to time too. By that I mean that randomly it feels like it's decided to kick in or out a bit of turbo, despite no real foot movement from me on the accelerator pedal. Very occasionally it seems to lose the turbo altogether, mostly when also displaying the "Engine Malfunction", so I presume that's a sort of limp home protection mode. I've been to several garages over the months, and costs are building up without success in pinpointing and curing the problem. This has included having various diagnostics done, filter and fluid replacement, full service, MOT, one sensor (I can't remember which one off hand).

I'd love to be able to finally get this cured, especially as I commute for work, so I'd love to hear from anyone who can give me some educated leads for the next trip to my techs!

[GreenV8S]

Have you checked the ECU for fault codes? That ought to explain why it is flashing warning lamps.

[JenningsCar]

I have had to rely on the RAC and the Garages for doing this and interpreting...they haven't told me the codes they see, but did indicate that they didn't seen anything conclusive. I'll ask and make a note when the next problem arises, as I'm sure it will! Sorry I don't have anything more specific data wise.

[Mignon]

Try this.

https://www.youtube.com/watch?v=MRSZufoYnMc

[JenningsCar]

Thanks for the link...the reset clears the "Service Oil" warning, but doesn't cure the issue itself. It's the issue I need to get fixed really.

[Mignon]

I would assume the ecu only knows the oil is due to be changed by when the service function was last reset and I'm not sure this would even create any running issues. It may be that the limp home stuff is a separate problem and I know from experience that blocked fuel filters can create all sorts of maladies on modern diesels.

[Little Pete]

You could have an issue with DPF regeneration. If the ecu is constantly attempting to do a regen, the oil quality will deteriorate rapidly and the ecu will flash the oil service lamp. As you say, the fault needs sorting not just the lamp turning off.