P0299 - Turbocharger/Supercharger "A" Underboost Condition

fafa

Registered User
So I had the engine warning light come on a couple times last week and so I bought an ODB2 scanner (Carista). It's giving me the above error code.

Before I book it in at the garage, does anybody have any suggestions of things I could check that might be doable at home?

The Carista app is quite good, I've enable the needle sweep and offside mirror dip on reverse functions.
 

fafa

Registered User
I've taken it to my local garage and he's said that he can't see anything obvious and to leave it until it gets worse. Well now the engine light as well the flashing glow plug light is on. It's come up with a code (05171) that I can't find anywhere is that even an error code or just an engine id? I'm not sure what to do next.

OBD2 - confirmed:

P0299 - Turbocharger/Supercharger "A" Underboost Condition



OBD2 - pending:

P0299 - Turbocharger/Supercharger "A" Underboost Condition



Engine:

05171



Ignition authorization:

02823 - Requirements for Locking the Steering Column Lock not met
 

fafa

Registered User
Local Garage couldn't find the issue so I've taken it to an Audi dealer, hoping they can find the fault at least...

60 or 80 quid (I don't remember which) for them to tell me it's Underboost on the Turbo, "yes I told you that was the code already"
plus another 140-280 to investigate further.. I hope to f*** it's just some faulty electronics when they call me tomorrow.

Any ideas on how I can navigate this with price negotiation?
 
With audi they are a law of their own. If the car is under 4 years old with full service history then they may help with costs.
 

fafa

Registered User
Update on this.. I've got the car back.. They spent 5 hours investigating but have charged me for 2 and waived the initial inspection fee and cdw on the loan car they gave me. They suggested further investigation around the turbo and actuator which they said felt a bit loose. Not sure what to do next, looking at VAGManchester as their hourly rate is cheaper but they'll want to start again from scratch.
 

fafa

Registered User
It’s bad news, they’ve identified what the problem might be but needs further investigation and they can’t do it. I didn’t quite understand what I was told on the phone but some some equipment which is needed is only available to Audi so it needs to go back to the dealers. The problem area is to do with the thing that switches between the two turbos. Sigh.
 

Stokka

Registered User
not something you fancy getting stuck into yourself fafa? sounds an expensive do if a dealer is going to do it
 

fafa

Registered User
not something you fancy getting stuck into yourself fafa? sounds an expensive do if a dealer is going to do it
Not really, well out of my league.. I just about managed to fit the cup holders and replace the fuel flap actuator.
 

fafa

Registered User
I sort of remember a control valve going on ours but for the previous owner who I knew.
Any idea how much it cost them to fix? I've just got off the phone with the dealer and they want to book it in for 5 hours to investigate, reduced hourly rate to 104 quid though.... I don't really have much option from what I can see.
 
Is was under warranty and I've no details just remember talking to him about a control valve

I know they complained when he put over 3k on the loan car lol
 

fafa

Registered User
The dealer just called me... They say it needs both turbos replacing because it's a single unit cost - £5800
 

Shinsplintz 101

Registered User
Warranty? If not try the "WTF I've only done xxxii number of miles & the cars only xxx years old....shed a tear...etc..." to the head of whatever dealership you bought the car from &/or are trying to get the repair done by. They might chip in for good will if it's FASH and only just out of the 100k/5yr bracket. Maybe. Certainly worth a try. Lay it on thick. What have you got to loose?

Otherwise - pucker up & bend over - no lube in the world is going to ease the pain, but at least you'll have two new turbos to play with!

I'd heard the repair costs on the turbos was brutal, shame your having to experience it first hand. Good luck.
 

Stokka

Registered User
ring around turbo specialists and see if any of them refurb them. i imagine plenty do, the problem and maybe the expensive part would be getting them took off the car by the same people, some are a walk in service only. for sure, this wouldn't be the route audi takes, they just replace
 

fafa

Registered User
Bit of an update. The dealer has offered to reduce the cost by 40% so 3400, which I appreciate but I still think it's ridculous that the turbo has gone due to wear and tear at this mileage with a FASH. I've also asked that guy on piston heads who had a similar situation what his amount was reduced to, so hopefully he can give me a bit more ammunition. My brother in law (Senior JLR engineer) says he thinks I should fight harder as it shouldn't need replacing due to wear and tear at that age. I've opened a case with Audi UK, and I'll see where it gets me. I've got a fairly nice Q3 as a courtesy car still so I'm happy to ride this out for a while.
 

The Black Panther

Adventurer !
Fa Fa Audi will take the p i zz. . PM me to discuss further.
Bit of an update. The dealer has offered to reduce the cost by 40% so 3400, which I appreciate but I still think it's ridculous that the turbo has gone due to wear and tear at this mileage with a FASH. I've also asked that guy on piston heads who had a similar situation what his amount was reduced to, so hopefully he can give me a bit more ammunition. My brother in law (Senior JLR engineer) says he thinks I should fight harder as it shouldn't need replacing due to wear and tear at that age. I've opened a case with Audi UK, and I'll see where it gets me. I've got a fairly nice Q3 as a courtesy car still so I'm happy to ride this out for a while.
 

Shinsplintz 101

Registered User
Push the dealer to get as close to 2k as you can then bite their hands off. Remember, FASH & the warranty on the parts & labour for such a potentially expensive part will certainly recoup any monies when it comes to resale. Should you choose to keep the car you don't have to worry about turbo failure like the rest of us :)

Buy cheap. But twice.
 

fafa

Registered User
Just an update on this.. Car is back with me and has a new turbo installed. Total cost ~£3500, waiting to see if I can get my next service free and a discount on a new warranty from Audi Customer Service rep. I'm considering writing a letter to Audi about the whole thing but to be fair to the dealer I think they've done what they can. On my next car I will definitely make sure it has a long warranty, kia stinger?
 

fafa

Registered User
Unbelievable. Just taken the car for a dr Be on the motorway and limp mode comes on. Carista says it’s the same error code. Fuming
 

fafa

Registered User
Any update on what caused it?
Yep, I took it back on Tuesday for them to inspect.

Today they've told me that they have replaced a sensor. I asked the obvious question, if it's the sensor why did the Turbo need replacing? I was told that the sensor has been damaged because of the faulty turbo.

I'm extremely sceptical about this explanation as it's exactly the same fault code. How can a Turbo suffering from wear and tear cause a sensor to go faulty?

When I got the car back I didn't notice any improvement in the performance, which I was expecting to have as the old turbo was faulty.

I've not seen any evidence from them that the Turbo needed replacing and have taken them at their word so far. I'm going to ask for the diagnostic report on the Turbo and any other evidence they have that it was faulty and see what they say.

I'm going to speak to the Audi specialist garage I took it to about this explanation and see what they say and I also think I might speak to a consumer advice body about it.

I'd appreciate if if anyone else had suggestions..
 

Rhyso

Registered User
Looking at the timeline the car faulted the same day you had it back??

If the sensor was faulty why didn't it show up when they test drove the car after putting it back together? Did they actually carry out a road test?

I'd want to know what sensor it is and where in the system is it. The only way I can see if being affected by the turbo is if oil was leaking past the seals and therefore got into the sensor?

I can appreciate intermittent problems are hard to trace but it looks like Audi have picked the most expensive item to replace rather than doing further fault finding at great cost to yourself :(
 

fafa

Registered User
Looking at the timeline the car faulted the same day you had it back??

If the sensor was faulty why didn't it show up when they test drove the car after putting it back together? Did they actually carry out a road test?

I'd want to know what sensor it is and where in the system is it. The only way I can see if being affected by the turbo is if oil was leaking past the seals and therefore got into the sensor?

I can appreciate intermittent problems are hard to trace but it looks like Audi have picked the most expensive item to replace rather than doing further fault finding at great cost to yourself :(

Not quite. It happened 5 days after I got the car back but it was the first time I took it on the motorway with the kids in the car. I believe them when they said they road tested as it would appear to be the case that the additional weight of passengers is part of the conditions which causes the light to come on.
 

Rhyso

Registered User
Ah right; saw Saturday in both your posts so it looked like the same day :)

So under full load conditions then? What about if you're on your own and plant your foot?
 

fafa

Registered User
Ah right; saw Saturday in both your posts so it looked like the same day :)

So under full load conditions then? What about if you're on your own and plant your foot?

Seems fine although I didn't give it the full beans as it's a brand new turbo and thought it should bed in a bit.. I was trying to get it to limp on my drive to the dealer by using Sport and Manual and shifting around the gears, accelerating, cruising at 50,60,70 but it didn't happen.
 

The Black Panther

Adventurer !
Audi will try and fob you off. I doubt the turbo needed replacing. Trouble is it will be an exchange unit and the old unit will be back at manufacturers being refurbed so you have no way of inspecting it now. Been here with Audi before a long time ago when they advise they change out a perfectly serviceable turbo unit and I said no and pinpointed the real reason for the car not boosting. That was some 12 years ago now.
 

fafa

Registered User
Went to pick it up today after sensor replacement and 40 mile test drive. Drove it for 10 mins, light came on.
 

Rhyso

Registered User
Went to pick it up today after sensor replacement and 40 mile test drive. Drove it for 10 mins, light came on.

Must be your driving style :racer:

On a serious note that is properly gutting :(
 

fafa

Registered User
Must be your driving style :racer:

On a serious note that is properly gutting :(

It was "lucky" that it came on. I'd stayed on the M60 for an extra junction as the temp gauge had just hit 90 so I thought I'd stay on to flick the paddles and open it up a little.

They've given me a new A4 2L TDI to drive about in whilst they carry on looking at it. It's quite punchy and a rather pleasant drive.. Better than the Q3 they gave me last time. An upside is I'm getting these extended test drives. If it happens again I might see if they have an SQ5, fancy a go in one of those :)
 

fafa

Registered User
Update: They have now told me they need to replace the EGR valve.. Anyone know if a dodgy EGR valve could cause the Turbo to be damaged somehow? I suspect this is what they are going to tell me when I next go to pick it up.
 
I`d be asking if this was the original issue. Have they given you a price for the fix they are doing now ???? if not it might be free gratis
 

fafa

Registered User
I`d be asking if this was the original issue. Have they given you a price for the fix they are doing now ???? if not it might be free gratis

I will be doing that. I had a senior technician explain to me last time that the fault with the turbo was measured using different equipment to the sensor that was faulty and so the turbo was definitely faulty too. I'll be definitely asking to speak to him again to explain how they test the turbo without the egr valve. They haven't told me it will cost anything and they've gone ahead and ordered the part so I'm expecting no further charges, but I'd rather they refund me the cost of the turbo and I'll pay for the egr valve to be replaced.
 

fafa

Registered User
OK, car back with me now. I did my best to recreate the conditions for the light to come on but (holds breath) it appears to be fixed. Engineer explained that they charged the turbo to diagnose it and that is independent of the egr valve so definitely needed replacing although he maf/map sensor probably didn't. They haven't charged me to replace sensor or egr valve so just the replacement turbo. I think I'll write to Audi UK about the turbo issue but the dealer has been pretty good in the way they've handled the whole thing.
 

Claudiu T

New Member
OK, car back with me now. I did my best to recreate the conditions for the light to come on but (holds breath) it appears to be fixed. Engineer explained that they charged the turbo to diagnose it and that is independent of the egr valve so definitely needed replacing although he maf/map sensor probably didn't. They haven't charged me to replace sensor or egr valve so just the replacement turbo. I think I'll write to Audi UK about the turbo issue but the dealer has been pretty good in the way they've handled the whole thing.
Hello! I'm experiencing the exact same problem with an single turbo 2017 Audi A6, 2.0 TDI, 150.000 km on the odometer.

Idle mode (indicatet by a yellow flashing spiral on the display - that's the only signal that I recive), appearing totally random, mostly on highway (speds over 160 km/h) and only once at about 110 km/h, when throttling the car!

I recieved 2 fault codes on the testers so far:
- P0088 (fuel rail preasure - preasure to high)
- P0299 (alimentation preasure regulation - preassure under the regulation values)
(sorry for the texhincal expressions)

I went for a full technical/mechanical/electronic check on the TURBO and all parts related to it (even EGR, pipes etc.) and the result (from a specialised turbo service) was: TURBO totally OK !!

Another 2 services stated that TURBO needs changing, even on this no. of km (over 2500 euro)!!

Please tell what sensor exactly did you change on your car beside the EGR valve and if that finally solved the problem on your car?
And also, could you mention the type of your car (year, motor).

Thanks a lot and good luck!
 
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