x1 e84 Engine Malfunction after work

[rkl 0]

Hi guys
hoping to get some pointers on what I should check.
I have had a issue with oil in the coolant expansion tank, with suspect oil cooler.
Yesterday I changed the Oil cooler, flushed coolant, changed expansion tank (old tank was too hard to clean and level sensor broken).
At the same time I changed oil and filter.

Looked fine, no leaks, all happy.
Went for a drive to get oil level reading, and after warming up, gave it a bit of throttle. Got the ding engine malfunction reduced power. 
Car drives fine but feels like no more boost.

After a cold start no errors until I reached the motorway (3km) at which point i had to accelerate more, got the ding at 75kmph.

Have done a scan on INPA but engine error codes are in German.

So looking for ideas on what It could be, before I take into dealer.
Used a fully syn 5w/40 oil, could this do it?
Or oil cooler not tight enough?

Car is a 2012 x1 28i

[E30 325i Rag-Top 2956]

Google the error codes, or use a translator to work them out. Otherwise it is just guess work, too many things that could be causing it, might be totally unrelated to the work done even.

[KwS 2425]

Translate.google.com or even better, the Google translate app on your phone.

Pissing into the wind otherwise, not knowing what the codes are. 

[rkl 0]

Will pull some codes tomorrow and see what I can come up with, Thanks

[rkl 0]

So checked codes again

Got 2c57.

Boost leak or faulty pressure sensor. Anyone had the same error on the n20. Google shows me alot of results wiht the n55.

Could be I got coolant on the pressure sensor? Going to look on realoem now, but if someone can point me in the direction of the sensor that would be awesome.

Edited April 25, 2019 by rkl

[M3AN 4016]

I know naught about these engines but I doubt you could stuff up the sensor by getting coolant on it.

That you had oil in you coolant is interesting... does the oil cooler have a water jacket? Otherwise I'm not sure how the oil cooler could contaminate the coolant.

Anyway, with any boost pressure fault be sure to check the wastegate is closing correctly.