P0299 Code

[WarrenB]

Van kept throwing up the traction control light and the nicely vague engine malfunction error and going into limp home mode. Plugged it into Forscan and came back with MAF sensor and MAP sensor faults. Replaced them both, cleared the error codes and it was fine for about 5 miles.

Now it’s doing the same again but coming back with P0299 instead. Ran live data on Forscan and alls ok until the VNT position gets to about 24% (as attached) and that’s when it throws up the errors. It’ll stick there until the engine is restarted, then alls fine again until it gets to 24%.

How likely is it that the turbo itself is knackered? Or could it just be the actuator that’s sticking and needs freeing up?




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[knobby1]

Van kept throwing up the traction control light and the nicely vague engine malfunction error and going into limp home mode. Plugged it into Forscan and came back with MAF sensor and MAP sensor faults. Replaced them both, cleared the error codes and it was fine for about 5 miles.

Now it’s doing the same again but coming back with P0299 instead. Ran live data on Forscan and alls ok until the VNT position gets to about 24% (as attached) and that’s when it throws up the errors. It’ll stick there until the engine is restarted, then alls fine again until it gets to 24%.

How likely is it that the turbo itself is knackered? Or could it just be the actuator that’s sticking and needs freeing up?




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Will more than likely be the EGR valve causing the MAF and MAP sensor codes....very common. Way too many MAF and MAP sensors are replaced for no reason...they very rarely fail. When the EGR valve fails mechanically the air flows/pressures are not what the PCM is expecting to see and it throws up a MAF or MAP fault code....essentially a call for help.

If your turbo actuator is sticking, it may be the internal turbo vanes hanging up. Pop the actuator arm off and see if the little lever on the turbo itself is free to move...if it is free, the electronic actuator itself may not be well.....There is a "turbo function" test within Forscan. If the vanes are not free, you'll need to pop the turbo off, remove the turbine housing and clean out all the carbon/soot/rust to free the system up.

Lord Knobrot

[WarrenB]

I did think it was odd that both the MAF and the MAP would go at the same time. But when i changed them both and the codes cleared and all was fine I thought it was just a coincidence.

Interesting about the EGR, never actually thought of that being the issue but that makes sense. It threw up the same MAF and MAP errors again on the way home so you're probably spot on.

I had another poke around when I got home tonight but was getting dark so couldn't actually do all that much. It's also showing an ABS error now so I've ended up booking it in to the garage for them to have a look.

As it's my only vehicle I'm not too confident at sorting it on my own if there's a risk I'll end up borking something! I'll give the turbo function test a go though, nothing to lose there I guess and it'll help narrow things down a bit.

Cheers

[knobby1]

It's also showing an ABS error now so I've ended up booking it in to the garage for them to have a look. Cheers

Have you changed tyres recently or done any work on the brakes..??

Lord Knobrot

[WarrenB]

It's also showing an ABS error now so I've ended up booking it in to the garage for them to have a look. Cheers

Have you changed tyres recently or done any work on the brakes..??

Lord Knobrot

Not any time recently. Brakes were done last summer and had a punctured tyre replaced a couple of months back.

In fact, the only thing that has changed relatively recently is I’ve been putting a bit of Redex in with every tankful to see if that helps with winter fuel economy. As it goes it makes zero difference, yet premium diesel does noticeably improve things.


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[TheCake]

fuel quality definitely makes a difference in mpg's i never fill up my diesel with supermarket fuel any more, an old mechanic friend would always say never use it as its full of crap, lucky for me i've got an esso nearby that is normally at 1.46 which has helped with the pain felt in my wallet when i fill up.

[WarrenB]

Think the issues have been solved! Ran some Revive Turbo cleaner through it today to clean up the turbo and EGR. Does seem to have made a difference, can hear the turbo spin up a lot quicker now, and the EGR valve sounds a lot more audible when its doing its self clean when turning the engine off. Or I could just be imagining it....

Anyway...

The MAP error wouldn't go away. Nor would the ABS error. Had a look at the 'new' MAP sensor I got from the auto spares place. On closer inspection it looked very much not new, so went to Ford and got a proper brand new FoMoCo one. Fitted it and tried to go for a drive up the road but ended up back in limp home mode.

Checked the live data on ForScan and it was showing the VNT position stuck at 25% again. Cleared the codes and left it recording the live data, just to confirm it was still moving around but getting stuck at the same spot. Turned the ignition on and noticed it drop from around 70% all the way down to about 9%. Never seen it do that before...

Knocked the USB cable out of the laptop so it stopped recording, but plugged it back in again and took it for a quick drive up the road. No errors or limp home mode. Carried on until things got up to temperature and then gave it a bit of an Italian tune up. No issues whatsoever.

IMG_3910.jpeg

As you can see (green line, third from the bottom) it got to 19%, and got below 25% on more than one occasion.

Could the faulty MAP sensors have been telling the actuator to open/close to 25% despite the turbo expecting more, hence the underboost fault? And then the new working MAP just needed a calibrate itself with the actuator?

All seems to be fine now though... hopefully!

fuel quality definitely makes a difference in mpg's i never fill up my diesel with supermarket fuel any more, an old mechanic friend would always say never use it as its full of crap, lucky for me i've got an esso nearby that is normally at 1.46 which has helped with the pain felt in my wallet when i fill up.

I've definitely noticed this over the years. I only tend to fill up at Texaco which the van seems happy with. Few years back I filled up a few times at Tesco and noticed a notable difference in the way it drives and MPG dropped slightly too. With Texaco Supreme premium diesel it runs a lot smoother, and get around 2 or 3mpg better on a long run. Gets expensive for a full tank though, so going to fill up every other tank with Supreme over winter and probably once a month over the summer.