V50 Electrics : Reduced engine performance light then total power loss

[nickinfrance]

Hello to all,

A first post. I have a 2009 V50 1.6d with about 130,000 miles.I don't have the service records, but believe DPF was changed as required at 75K. I don't have codes, my visit to Volvo dealership in my trusty (and crusty) V70 resulting in the advice that I replace diesel fuel filter and, if necessary, return to get codes read. I don't thnk I can safely get to dealership and am hoping for a DIY solution in advance of a tow.

Several months ago I started getting a reduced engine performance light sporadically (or rather the French version). This problem has steadily gotten worse. When I have the problem, it usually kicks in after about 10 minutes of use. First the reduced performance light goes on (and engine has less, but still useable power) and then (after a few minutes or perhaps not at all) the engine cuts out totally. Very scary and we have had some very close calls. After a few minutes of waiting, the car will start up...but usually only for a few minutes. Then engine dies again

Curiously, the problem goes away as I proceed to go through a tank of gas, until I reach a point where it runs normally. Several fill-ups down the road, and I'm sure that there is some issue with the fact of filling-up (or at least removing and replacing the gas cap). With each new addition of fuel (yes I have tried permium diesel..lesser fuel being an early suspect), the car will die almost immediately.

A couple of further clues,

I have a new Bosch 740amp battery and a new air filter.
I have run the vehicle with MAF wiring disconnected and the problem persisted
I can disconnect the MAF wiring with the engine running and the engine will still run. One forum suggested that this is indicative of a faulty MAF... BUT as noted above, the car will still cut out if driven without the MAF connected. So, if it is a faulty MAF, it is likely not JUST a faulty MAF. I was tempted to try and clean the MAF, but now think that this might be pointless.
The VOLVO dealership suggested that it might be the diesel filter. I have purchased this but not made the repair. Partly because issues as to eliminating air in the fuel line after installing the new filter were a bit daunting...and partly because another mechanic thought that the fuel filter suggestion was ridiculous and felt I should be focusing on air and not fuel.
That mechanic, first thought that running the vehicle without gas cap on might fix the problem (an air hose parallel to fuel line being blocked, I believe was his rationale). That actually seemed to work for about 50 miles, but then things were if anything worse the next day.
Aggressive acceleration will cause an almost immediate cut-out...nursing the V50 will limit cut-outs a bit.
My wife insists her running of heater exacerbates the problem. I;m not so sure as I don't put it on (she ignores my requests to do likewise)

Any help would be enormously useful, even if it is just to arm me as I take on the French Volvo dealership. I am comfortably in the "a little knowledge is a dangerous thing" zone, but occassionally think I am close to cracking it. And boy would that feel good!

[nickinfrance]

It turns out that it was as simple as replacing the diesel fuel filter. Which was recommended on several forums. Very grateful to those posters.

I am still extremely upset with Volvo that they would allow to exist a problem that completely shuts down the engine without warning. Pre-CPU days, this simply would not have happened. I do not exagerate when I say that this almost cost a life for us.

Yes, partly my fault, to use the car at all when a warning light came on. But that warning, unlike many others, does not suggest that the car be stopped immediately or that it is categorically unsafe to drive.