Audi A3 1.9 tdi Limp mode after turbo vanes cleaned

[Ch4ndler]

So far i have spent £400+ on trying to fix this problem. Its the standard limp mode when pushing the car hard in 3rd/4th/5th gear over 3000 revs. I went to one garage who charged me £120 for some Mr Muscle to be pumped through the turbo, then spent £290 having the turbo removed and cleaned at a different garage.

The car has two different modes:

1. I turn the car on and the turbo doesn't kick in till 2200 revs, car feels slow and sluggish.
2. I turn the car on and the turbo kicks in at 1800 revs, fast acceleration etc.

If it decides it wants to be in mode 1, I can drive it for 5 minutes, turn the car off and back on again and it switches to mode 2 (not limp mode as I am well aware what this feels like!)

Anyone have any ideas what may be the cause?

EDIT: Forgot to mention, the vag-com code is the standard P0234 - Boost Pressure Regulation: Limit Exceeded (Overboost Condition).

 

[Geraldy212]

Have you checked that the turbo vane actuator mechanism is working properly, and not sticking? Good luck.

 

[S3 AEX]

Had this problem on my A4 tdi and our lass's golf tdi, the turbo cleaning solutions are crap in my opinion. It turned out to be the boost sensor on both cars. About £30 from dealers! I know it's to late now but you should've started with the cheapest options first, boost sensor then your boost control valve (n75) also check all your boost pipes.

 

[Ch4ndler]

Had this problem on my A4 tdi and our lass's golf tdi, the turbo cleaning solutions are crap in my opinion. It turned out to be the boost sensor on both cars. About £30 from dealers! I know it's to late now but you should've started with the cheapest options first, boost sensor then your boost control valve (n75) also check all your boost pipes.

I'm hoping it it a sensor that's playing up as it would tie in with the car being fine one day and sluggish the next.

How did you come to the conclusion it was the boost sensor?

 

[B5NUT]

Have you disconnected the battery? I was also get over boost error and replaced the turbo (It was faulty) and was still having the same problem, Disconnect the battery over night and had no problems since.

 

[Ch4ndler]

Have you disconnected the battery? I was also get over boost error and replaced the turbo (It was faulty) and was still having the same problem, Disconnect the battery over night and had no problems since.

If this works you win 1 x internet.

 

[B5NUT]

It fixed in in my case, but it's worth a try and not going to cost anything.

 

[desertstorm]

Have you actually logged the boost using the measuring blocks to see what the specified and actual is. Failure of the MAP sensor will give that code, Quite easy to see when you log the boost it will be sitting at 3000 even at idle. Had two guys at work with exactly this fault within a month of each other. One a Passat the other an Audi A4. A faulty N75 can also cause over boost issues.
try logging measuring blocks 8 and 11 and see whats going on.

Karl.

 

[S3 AEX]

I'm hoping it it a sensor that's playing up as it would tie in with the car being fine one day and sluggish the next.

How did you come to the conclusion it was the boost sensor?

I had the same codes as you so after checking the boost pipes I decided to remove my map (boost) sensor and clean it up, was ok for a few days after this but then started again. After that I just decided to take a punt and change the sensor an hey presto it sorted it, the golf I decided to change it just with the knowledge of what I got from the A4 and that was fine after as well. My sister had the same prob on her golf as well but hers turned out to be the n75 as they call it. Hope you get it sorted but I would certainly change one or both of the sensors for the sake of £70ish.

 

[S3 AEX]

They should look the same or similar to these

 

[Ch4ndler]

I have spoken to the garage who cleaned the turbo and mentioned the n75 and boost control sensor to them. I also asked if they cleaned the actuator whilst the turbo was off and they hadn't. Its going back to the garage this week.

Before I end up paying them to change the sensor and valve I want to try loosening the actuator myself. Does anyone know if I can get to the rod without using a ramp? Any instructions would be appreciated.

 

[Ch4ndler]

UPDATE:

Well I got the car back a week ago, the garage told me they cleaned the boost sensor and put some DPF cleaner through it (my car doesn't have a DPF?). First drive down a duel carriage way and it went into limp mode straight away.

That's two garages the car has been to and I have lost faith in both, it seems no one wants to spend any time on the job. Am I doomed to giving it to an Audi garage? I wouldn't have minded buying a new turbo if its what a garage had recommended but now I'm £500 down with the problem remaining.

Does anyone have any recommendations on a garage that will thoroughly test/find a solution to the problem? I am willing to travel to get this sorted.