Hey guys, i'll give you the symptoms:

slight boost lag

p0299 intermittent, once every 100 mile or so

No burning oil

No hissing from pipes (checked intercooler and turbo)

History

Previous to the turbo situation the car was offering the code for overboost

blew a turbo 1500 miles ago, got a recon fitted and dpf gutted

Recon snapped the exhaust bearing 600 mile into it's life

At that point I hadn't got the funds to get the dpf mapped out

New core fitted to recon turbo

Dpf mapped out

Egr blanked

Egr mapped out

Engine flushed

Oil changed several times throuout this process including sump removed at first turbo chsnge and cleaned gauze, sump floor

Oil feed pipe replaced at second turbo change

Opinions?

My focus 1.6tdci intermittently went into limp mode over the space of 2 years everytime putting a code out on my eBay OBD2 reader(£5) of p0299 turbo underboost, I took it to a local garage who couldn't find anything wrong, took it to a dealership expecting the worst(a new turbo and a massive bill! ) they plugged it in and found the fuel filter was full and needed changing, £170 for the diagnostics and fix :) my advice is if you get these symptoms, change the diesel filter first as a local garage will do it cheaply could save you being ripped off for a new turbo!

ive noticed that quite a bit, any hint of an issue with the DV6 and everyone is all over the Turbo blowing up.

a lot of engines blew up most of which could have been prevented with a bit of TLC but I think some garages expect it to be the issue now so don't bother with anything else.

have you cleaned and or replaced the MAP and MAF? a surprisingly large amount of oil is sucked in to the inlet manifold, that can build up and cause all sorts of issues.

The recon turbo, was it a genuine model, are the vanes moving correctly?

Others on here are much better at this kinda thing but in my mind, if your getting underboost then its either

a leak (id have thought that would give it all the time tho)

a sensor problem, ECU only knows what its told

The Vanes aren't moving correctly (sticking perhaps, might explain the randomness of it)

Not spooling up or rotating correctly because of something

Had this code on a mates turbo petrol (bit different I know lol) but his was a simple turbo actuator solenoid. I'd also check the boost (MAP) sensor as already suggested.

Did the car have a rubbish map or tuning box fitted at some point before the first turbo failure? That's a common culprit for overboost and cost me a turbo back in the day haha.

On 19/01/2016 at 10:48 AM, RichardAce said:

My focus 1.6tdci intermittently went into limp mode over the space of 2 years everytime putting a code out on my eBay OBD2 reader(£5) of p0299 turbo underboost, I took it to a local garage who couldn't find anything wrong, took it to a dealership expecting the worst(a new turbo and a massive bill! ) they plugged it in and found the fuel filter was full and needed changing, £170 for the diagnostics and fix :) my advice is if you get these symptoms, change the diesel filter first as a local garage will do it cheaply could save you being ripped off for a new turbo!

Update,  symptoms came back again so got the fuel filter changed again and tank cleaned out,  but alas still no joy,  finally took it to a local garage recommended to me who. Could not find anything wrong until he opened the air box.   I'd been changing the oil and filters myself for 3years but not the air filter which was now clogged up causing oil to be drawn out of the engine onto the maf sensor clogging it up! Lesson learned! Always change the air filter every year! Oops! 

Update again! Changed the oil and noticed the rubber end of the flexi pipe going from airbox to turbo had split where the metal jubilee clip clamps to the turbo had split where I had over tightened it, this I think has caused all the errors and limp mode problems. Bought just the rubber part on ebay for £6 and its running better than ever 🙂

On 11/25/2018 at 11:27 AM, RichardAce said:

Update again! Changed the oil and noticed the rubber end of the flexi pipe going from airbox to turbo had split where the metal jubilee clip clamps to the turbo had split where I had over tightened it, this I think has caused all the errors and limp mode problems. Bought just the rubber part on ebay for £6 and its running better than ever 🙂

Good man, good of you to provide an update as it might help someone else in the future.