A4 TDI 170 P0299 Underboost on occasions

[Tame Technician]

gogsboy said:

Cheers mate, great information there.

With regards to my talks with the Audi dealership it was not just the basic service advisor, it was someone higher up the chain, forget their exact title but they did seem to know more than your average person that you speak too.

I would have thought they would have covered this avenue as you mention there is a TPI about it, whatever that means

Is there some document available explaining that it is a known weak point

Technical Product Information.

Audi are very funny about releasing information about known faults. I really cant upload the details of the TPI on here, or anywhere on the internet. If I can find it somewhere else with google, because I know what words to search then i would do so but I cant for this one. The TPI basically details the likely causes of P0299 and advised tech how best to fix it. Including the test on the manifold flap actuator, and if everything checks out ok the required SVM code to update the software in the ECU.

The actuator is something silly like £9 or £12 i cant remember. Take about an hour to fit.

DO you know nayone with a Mityvac?, test it yourself???

[Tame Technician]

Cats said:

TT do you have any experience of Bluefin/Superchips remapping on this engine? Would the remapping overlook any underboost problems and by-pass the problematic performance or if there is a vaccuum problem would the performance still suffer?
Bluefin suggest some very good performance enhancement figures for this engine (+40bhp) which I assume are achieved by by-passing certain sensors etc.
I have always found the power delivery of this engine rather disappointing - very much on or off and not smooth and am considering this route but I guess that a vaccuum fault realistically needs correcting first.

We dont see many chipped cars, have no idear who the best people are, only that most dont know what they are doing.

If you have an underboost problem , chiping the car isnt going to fix it.

The correct way to chip a turbo car is to raise the boost pressure (within sensible limits for the size of turbo and intercooler fitted to the car) and at the same time increase the amount of fueling across the rev range to match that increase in boost.

The turbo wont make more boost in the lag parts of the rev range, it will able to make a far bit more than standard tune through the mid range, and a small amount more at max rpm. SO typically with a remap you will find the off / on character will get worse, but the on bit will be a bigger push.

[Cats]

TT many thanks for your explanations. If only I could have known about this months ago - I may have had a better feeling about the car. The first few postings make so much sense about this problem especially the low rpm with wide throttle openings. Funnily enough I came back from Cornwall last night towing. The fault appeared rather quickly but I managed to control it by keeping the revs above 2k and not letting it labour too much. However and this is the part I still cannot understand, and the car does this solo after about two hours driving there appears to be a different phase of the problem where the off boost performance becomes extremely sluggish and the turbo cut in doesn't start until almost 3k rpm and I have to keep the revs above this. This is when I get the hot component or oil smell from under the car with the different idle sound. Could this be a regeneration of the pdf(I think that's the one) filter?? If I keep driving the fault eventually goes away and the performance returns after about 10 minutes. So frustrating!!

[Tame Technician]

Cats said:

TT many thanks for your explanations. If only I could have known about this months ago - I may have had a better feeling about the car. The first few postings make so much sense about this problem especially the low rpm with wide throttle openings. Funnily enough I came back from Cornwall last night towing. The fault appeared rather quickly but I managed to control it by keeping the revs above 2k and not letting it labour too much. However and this is the part I still cannot understand, and the car does this solo after about two hours driving there appears to be a different phase of the problem where the off boost performance becomes extremely sluggish and the turbo cut in doesn't start until almost 3k rpm and I have to keep the revs above this. This is when I get the hot component or oil smell from under the car with the different idle sound. Could this be a regeneration of the pdf(I think that's the one) filter?? If I keep driving the fault eventually goes away and the performance returns after about 10 minutes. So frustrating!!

Burning smell and poor throttle responce (less optinum drivability) is almost certainly DPF "Diesel Particulate Filter" regeneration.

If you get a regen every single drive it suggest there may be a problem with the pressure sensor the car uses to monitor the DPF. Regen should happen every 600 miles or so.

[gogsboy]

Can the actuator be bought seperately for sure?

Don't suppose you know the P/N for it.

If this does not solve, where would you be headed next?

I've heard all sort of stuff from using innotec turbo cleaner to adjusting rod length

[Cats]

Car is in the dealership and what do you know they think that they have found the fault. Inlet manifold flap and EGR valve!!!!! I haven't got it back yet as the parts have got to be ordered in.
Thanks TT - 2 bl***y years mustn't get my hopes up.

[gogsboy]

Tame Technician said:

Technical Product Information.

Audi are very funny about releasing information about known faults. I really cant upload the details of the TPI on here, or anywhere on the internet. If I can find it somewhere else with google, because I know what words to search then i would do so but I cant for this one. The TPI basically details the likely causes of P0299 and advised tech how best to fix it. Including the test on the manifold flap actuator, and if everything checks out ok the required SVM code to update the software in the ECU.

The actuator is something silly like £9 or £12 i cant remember. Take about an hour to fit.

DO you know nayone with a Mityvac?, test it yourself???

Cheers for all the info TT.

Your good self excluded, are Audi techs known for not knowing the full info regarding TPI's, guess they have to be bothered to go and read the info in the first place?

I managed to talk with 2 master techs and both didn't have a clue what I was talking about, doesn't put your mind at ease at all, then one went and checked up and came back saying it mentioned it along with possible dirty injectors.

One dealership said you cannot speak to any of the techs.

Was hassle getting the part too, parts didn't have a clue but managed to talk to someone in TPS who located the part on the system as 'vacuum unit'?

Indy garage changed it but charged a lot more than 1 hour, so far not had boost fault....but then it wasn't happening with me before, need to get the wife to do some driving

[onmeheadson]

Cats said:

Car is in the dealership and what do you know they think that they have found the fault. Inlet manifold flap and EGR valve!!!!! I haven't got it back yet as the parts have got to be ordered in.
Thanks TT - 2 bl***y years mustn't get my hopes up.

How did you get on with this? Is your car ok now?

My Octavia vRS PD 170 has almost exactly the same symptoms as yours. I'm being told its a problem with the actuator or movement sensor on the actuator.

[R1LLE]

Hi

New to forum and wondered if anyone had fixed there P0299 problem?

I have an Audi A4 Quattro 2.0PD 2007 50000 miles. Over last weekend the glow plug light came on and started to flash and went into limp mode. Turned off vehicle and started again all ok and drove fine.
I have scaned the vehicle and it was the Boost pressure regulation P0299 - 006 Control range not reached fault.
If this is any good the freeze frame data states: RPM 2304 / min. Torque 272.0 NM. Speed 104.00 Km/h, 70.59%.Voltage 14.13V. Pressure 2193.9 mbar. pressure 1767.9 bar.

The last two figures of pressure. I am not sure what they are. (target or actual pressures or where they are measured it does not say).
Have had a quick look at the vac pipes and all look ok. I have yet to test the vaccum on the pipes.
I have tried driving the vehicle with large throttle openings as mentioned in the previous posts and driving the vehicle at a resonable pace but I can't get the light to come back on.
I also ran a full system scan and this was the only fault stored at this time.

Any ideas?

Did anyone actually fix there problem?

[Tame Technician]

2100 millibar is specified (what it should be)
1700mb is actuall, (what pressure is generating at that moment)

All the other info is there, you were doing 2300rpm at about 60mph. Cant remember if the 70% is throttle pedal demand or the duty cycle of the turbo boost solonoid. Thinking about it must be throttle or would be nearer 0 or 100 for the solonoid.

So to try and replicate you want to be in what ever gear gives you 2300 at 104km/h and use 70% throttle.


Usual causes of this, as mentioned abouve really, manifold change over actualor diapham is always the favourite.

[Tame Technician]

Tame Technician said:

P0299 really shouldnt be that hard to fix, it can only be about 4 different things in that engine.

If its got a new EGR valve, N75 and there are no vac leaks, (weather from the know troublesome vac actuator on the manifold flap), or any where else in the vac system, then it is possible the turbo vains sticking and then a turbo is the only fix. But I have to say that is unusual, when turbos stick its usually in the other possition and you get overboost rather than under, so dont be sold a new turbo just yet.

There is a software update to prevent the ECU falsely detecting an underboost situation that isnt there, but I havnt had any success with this fix, we did the update to a few cars that had p0299 intermitantly, they all road tested ok but then came back again with the same problem and further issues were then diagnosed.

You need someone who really knows what there doing to look at it, i find it hard to believe an Audi centre would just put an N75 on without being 99% sure that was the fault, but from your post I have to say I'm not sure they have tested it propperly.

Maybe go into the audi centre and ask to speak to the master tech about it. When you phone them you get a service adviser who doesnt really understand how the car works and just relays 2nd hand what the tech told them.

I would say 90% of 170PD TDI's I have tested with p0299 has either needed the manifold vac actuator or there has been a masive boost leak somwhere like holes intercooler or split hose (you would surely hear this, loud hissing on boost)

The other 10% the engines wouldnt rev to 4500rpm due to either blocked injectors or low fuel pressure, the poor combustion at very high revs meant there wasnt enough exhaust output to keep the turbo spinning and an underboost code was logged. Often customers would even know the engine didnt rev as they changed up well before this point and the only simpton they reported was intermitant going into limp mode.

Go out and give it a drive trying both pulling from off boost 1200rpm in 3rd 4th through the range, and thrashing it right to the red line in 4th 5th, to see if you can make it play up.

If it fails in the low rpm range is likely a vacuum issue or the software needs updating, If the engine wont pull right the way to the red line and ECU notices an underboost right at the top of the rev range you may have a low fuel pressure or blocked injector issue.

It all here.

[R1LLE]

Thanks for that. Are the inlet manifolds reasonably easy to remove on these engines? And once removed what is the diaphram like to change? Will I need any gaskets for the rebuild of the manifold? When checking these vac pipes what pressure should they hold and for how long? Also are there any measurement blocks or live data I can read to diagnose further.

Thanks for your time and advise.

[R1LLE]

Would the inlet manifold diaphram give intermittent flat spots / hesitation if it was playing up? A symptom just like you have a faulty air flow meter (maf). As the car has also done this off and on for the last 18 months. It had a new genuine maf around 7 months ago and I have checked the egr on live data and is working correctly. It also had four new injectors and a wiring loom in the middle of last year via main dealer.

Thanks.

[Tame Technician]

R1LLE said:

Are the inlet manifolds reasonably easy to remove on these engines?

Yes quite straigh forward, one bolt is hidden inside, need the EGR and throttle/shutdown valves removed first to get to it.

R1LLE said:

And once removed what is the diaphram like to change?

Very easy with the manifold off, think its two torx screws

R1LLE said:

Will I need any gaskets for the rebuild of the manifold?

They are metal so you can generally get away without changing them, if you want to play it absolutly safe get an inlet manifold gasket and some for the EGR joints.

R1LLE said:

When checking these vac pipes what pressure should they hold and for how long?

When checking the vacuum diaphram on the manifold actuator, should pump roung to nearly 0 and hold it indefinatly, if its failed, you wont be able to get near 0 and will just loose a vacuum as fast and you can pump the mitivac.

R1LLE said:

Also are there any measurement blocks or live data I can read to diagnose further.

MVB 11 will give you the specified and actually boost pressures

Edited by Tame Technician on Wednesday 25th September 23:33

[Tame Technician]

R1LLE said:

Would the inlet manifold diaphram give intermittent flat spots / hesitation if it was playing up? A symptom just like you have a faulty air flow meter (maf). As the car has also done this off and on for the last 18 months. It had a new genuine maf around 7 months ago and I have checked the egr on live data and is working correctly. It also had four new injectors and a wiring loom in the middle of last year via main dealer.

Thanks.

Intermitant flat spots and hesitation is probably DPF regen, you cant generally tell if the manifold flap isnt moving.

In my experience peolpe mis diag MAF faults all the time.

The actuall symptom you get with a faulty MAF on a PD engine is no acceleration beyond a certain RPM, They boost up arround 2000 ish pull stongly up to 3300-3800 and it will just run out of puff. If you ever see a MAF fault stored in the memory its either a boost leak or an EGR fault.

This is almost the same as the blocked injector problem on the early 170's and often the only way to be sure was to plug a new maff in and or clamp the fuel return. IF you clamp the fuel return and it gets better, its fuel pressure or injector relaited, if you put a new MAF on and its better, then it was the MAF. Fortunatly at the main dealer there are always a couple of MAF's in stock if you need one for testing.

[R1LLE]

I thought the flat spots could be regen myself as my wife drives the car most of the time and i figured on her short journeys etc the car would be trying to regen but not get chance to finish off. So I did a forced regen on it and got the soot load down to 0% from around 40%, after doing this it has still flat spotted on various occasions.

If it helps the car seens to only flat spot and seem hesitant when the weather is warm, so in the winter months nothing at all runs fine etc.

On the boost problem, to identify what the cause is would measuring the vacuum to the turbo actuator by 'T'ing into the pipe with a gauge help?

I figure then if the vacuum drops as it hesitates its the flap loosing / lack of vacuum. If the vacuum is maintained or raise as it hesitates its the turbo sticking?

[philarmonic]

Anyone know the part number for the manifold flap?

My golf has had the same issue, VW have diganosed, only after me telling them what to look for after reading this!

But... they wont replace the flap, they will only replace the whole manifold and want £500 just for the part!

Sods!!

[sri16v]

I had terrible hesitation and stuttering problems with my Octavia VRS PD 170, I thought it was the egr valve, then the DPF.

Anyway cut a long story short I changed the seal in the boost hose that connects to anti shudder valve and egr and have had no problems since.

This problem had been going on for 6months and no one could replicate or find the problem, not sure if your having the same problem, but I never had any fault codes or lights come on.

[ssmotorretail]

Paul, I have been reading this in great detail as I have got the exact same fault with a a4 quattro 2.0 170bhp.

I have had a new EGR, a new Turbo and a new N75 valve fitted and now the garage is telling me it is the swirl flap actuator, I can't seem to get one from anywhere for this car, TPS only sell the complete manifold as do AUDI, I have found them online but when I ring to order it I am told that it will not fit my car,

I am over £700 into this problem and a manifold is over £500, It would be a massive help if you could advise me.


Thanks. Sam

[NewBee1]

My oil pump broke on my audi a4 2.0 tdi 140hp blb engine a couple months ago.
Also my turbo broke.

I sent my turbo in for renovation and after that my boost is delayed 1000 rpm. Car works fine otherwise. But nothing happens before the turbo kicks in (2800 rmp second gear) No leaks and sticky vanes. Had the car in for a check at audi and everything is fine.

I belive its something wrong with the aculator.
The boost comes sooner without the cable in the aculator in, but the boost is lower and goes into limp mode with to much acceleration.

Car worked fine before it broke down. I have drove like this about 4 months and nothing has changed.


What could be wrong?

Thanks