Audi A3 2.0 TDI with turbo issues (Limp Mode)

[westy123]

Hi guys,

I would really appreciate your help with an issue I have with my 2004 54 Audi A3 2.0 Tdi. I bought the car recently and after driving it on the motorway for the first time it lost power and felt like driving a car without a turbo. I pulled over and turned the engine off and switched on again, the car drove fine again with full turbo power - nice and responsive. I drove the car for another 10 or so miles then when driving up a hill the car went back into limp mode and the EML came on. I pulled over and called the AA who did a read and the code was an ECU fault (sorry didn't write it down so don't know exact code), the AA cleared the code and sent me on my way.

The car has been doing this daily and the EML light came back on the other day but this time the reading was an overboost code 16618 Boost pressure regulation Limit exceeded. On the advice of a friend I got terraclean to do a full turbo clean at the cost of £250 and this worked for about 60 miles but now the car is doing exactly the same thing again. I am getting so frustrated as when the car is running well its brilliant.

Anyway my question is should I change the EGR valve first as that was the first fault code (hasn't come back since being cleared), or should I be considering a recon turbo? The mechanic who plugged it in and gave me the overboost code code has said I need to change a part by the top of the engine (sorry I'm useless with cars and cant remember what it was called)

Any advice would be greatly appreciated!

Simon

[MarkTM]

Simon, first add your location to your profile, I have VCDS and you could be a neighbour and do a free scan for you but I'll never no unless you update.

What I'm saying is you need a scan to identify the problem before you start throwing more money at it.

A simple google shows this for the one fault code you can remember:

16618/P0234/000564 - Ross-Tech Wiki (http://wiki.ross-tech.com/wiki/index.php/16618/P0234/000564)

[zollaf]

what exactly did terraclean do for 250 quid. did they remove the turbo, strip it down , clean the vnt mechanism then put it all back together , or just throw some chemicals at it and laugh all the way to the bank.
a clogged turbo is the usual culprit for this code, but it could also be the n75 valve, but most likely the turbo and no amount of magic chemical will help with that. the fault can be confirmed by using live data to monitor the boost pressure and if it is the vnt, a new or rebuilt turbo can be fitted, or your existing one removed and cleaned.

[Fexo]

I have the same problem on motorways but not town driving (in fact it happened 3 times on my journey back from Angle and once going). Switching the engine off and on again cures the problem for a while. It has happened on rare occasions over the past few years in slow moving stop/start traffic but is now occurring on most motorway runs. The local independent called up the EGR specialist with the codes and he said that it is the EGR cooler and he sees several a week with this problem. I'm a bit pee'd off to say the least as it is 5-6 hours work + £300+ for parts and more if the electrics have to be changed. This is for a car that is less than 4 years old with 42K on the clock and needs £1000 worth of work from an independent and probably a lot more from Audi.

Looking on the net, I see that the Golf drivers are having a lot of EGR problems and a lot of repair work is being done on a "goodwill" basis (free parts + 50% off labour). Does anyone know of similar problems with Audis?

[westy123]

Hi Mark,

Thanks for your reply, I think I know somebody with a VAG.com machine, shall I get a scan and report back? The person who cleaned the turbo is coming back this week to check the V75 which I see is on the list of items that could be faulty on your list, so hopefully that might work.

I shall get a scan let you know

Thanks again

Simon

[westy123]

Terraclean just pumped some magic solution in, charged me £250 and told me the vanes are now clear and not sticking so it's an actuator problem. The mechanic has taken the actuator off and says it's fine.

Really lost as to how to proceed. If anybody on here is local and fancies fixing it for me I'm happy to pay £££ and bring it to you. I'm in Fareham, Hampshire

Mechanic has noted there is lots of oil round the intercooler pipe

Again thanks for your time and responses

[zollaf]

the man from terraclean is wrong. if he had ever stripped a turbo down and manually cleaned it he would know that he is deluded.

[westy123]

Hi Zolaff, with the code p0234 would you suggest replacing the N75 valve? I'm trying to get hold of my friend to get a VAG scan in the meantime

[zollaf]

boost limit exceeded, no, i wouldn't replace it, i would test the movement of the actuator arm on the turbo and if its not nice and smooth for all 19mm of its travel then i would strip and clean the turbo.

[Crasher]

Get the turbo off and PROPERLY rebuilt, not some snake oil flush! The carbon inside a turbo has to be blasted off with a bead blaster, not chemical is going to be able to move that. Terraclean is a bad joke.

[westy123]

The mechanic said the actuator was fine.

Hi Crasher, do you have any recommendations for a good company to re con the turbo?

Thanks for your help

[Crasher]

For me locally, Midland Turbo without hesitation, they are doing one for me at the moment.

[westy123]

What do they charge roughly? I assume I can get the turbo stripped and send it to them in the post?

[Crasher]

It varies depending on condition. You would send it, they strip it and then call you with a cost. They do huge numbers of BKD engine turbo's and lots for us.

[zollaf]

or to save time, order and pay for one, get it, fit it, then send yours back for surcharge. they probably have them in stock and can get one to you next day. saves your car being off the road for a few days. best to fit a new oil feed pipe at the same time.

[westy123]

Just as an update I have had a friend plug it into VAG.com and he has told me it is the N75 valve. I'm going to fit one tomorrow and if that fails then I'm going to use Midland turbos as I phoned them earlier and they were very helpful, thanks for the recommendation Crasher

[Crasher]

The one I dropped off with them first thing yesterday morning was ready by the evening and is already half back on the car. It is useful that they are only just across the car park from TPS so sometimes our TPS driver "Swervin Hervin" will pick them up for us.

[westy123]

Ok So I have ordered the N75 control unit £220 and will be having somebody fit it tomorrow morning. I've also bought a fuel filter, air fitler and oil filter so they can do a service at the same time as it is due one now. One thing that is very confusing is now the car has gone into permanent limp mode and even turning the key off and on again doesn't make a difference like it used to. It is also now kicking out a bit of black/grey smoke and this morning it was jerky and hesitant but this has now stopped. EML light came on and the new codes are : P0101 MAF or VAF curcuit range /performance problem, P0299 Turbo supercharger under boost!

Very confusing as before it was reading overboost before and now underboost, I'm hoping the new N75 will cure all this as im getting sick of this car, its driving me insane!

[Crasher]

That sounds like a split boost hose or intercooler, just had an A4 in this PM with the same problem, the hose from turbo to intercooler cross pipe was split.

[westy123]

Right I've fitted the N75 unit and it seems to have given the car it's turbo boost back. Unfortunately the car is still smoking (wasn't doing this originally but happened over the last few days). I still need to get a friend to clear the eml and fault codes. The car is also juddering quite badly now

Also will get somebody to check for splits on the boost hose.

Anyway thanks everybody for your help and suggestions so far

[NHN]

Total agreement with crasher, I've removed a number of turbos stripped cleaned & refitted & all back to new. The Mr muscle or Terraclean are a complete waste of money & time, they can not remove the burnt on exhaust crap, you need to strip & dremel each piece clean back to the bare metal, only this fixes the overboost issue when vnt is clogged.

[MarkTM]

There are plenty of 'how to' guides on the net, there may even be some on here, but my first search came up with this one:

http://www.audi-sport.net/xf/threads/guide-how-to-remove-turbo-and-clean-sticky-vane-which-causes-overboost.149599/

[Crasher]

That really does sound like a boost hose leak, the BKD is prone to leaking on the intercooler outlet and the coupling to the manifold flap.

[westy123]

Hi Crasher, the mechanic has diagnosed as the MAF as when it was unplugged there was no smoking or shaking. Fitting a new one today and I'm hoping that's the end of my woes. I will update how he gets on. I asked him to check the boost hoses on your recommendation so he is checking those too while the car is in

[westy123]

right as an update a big thank you to everyone who helped and contributed especially Crasher, your advice was spot on.

Replaced N75 and replaced the turbo hoses as they were ******* and the car drove great, with no limp mode, no smoke or shuddering.

I've now sold the car as I'm getting another Audi.....

Thanks guys really appreciate it!