Hello all! I'm having some problems with my 07 mcs "boost pressure deviation" along with the car going into limp lode because of this the car IDLES VERY POORLY, but is fine when driving. I have been reading forums and have not seemed to stumble upon anyone with the same 2 symptoms I already have replaced the pressure inverter because my dealership told me too but it did not fix the problem so I am here to ask if anyone may know what is wrong, I don't feel like playing put more parts on the mini because I am trying to fix the car to sell it! The car used to have an unmetered air leak but I have not had that code for quite a while.. Just the boost pressure deviation" with rough idle, car also idled rough with air leak but there is no air leak code anymore!

 

Boost pressure deviation points to two areas: the turbo and the pipes leading from the turbo to the intercooler and from the intercooler to the air box. Check every single hose and hose clamp on those parts to see if they're cracking or not mounted flush. Otherwise it could be a failing diverter valve or wastegate on the turbo.

 

So you had an air leak but never fixed it? Now you're wondering why your car doesn't idle? Fix that air leak.

Also, is "boost pressure deviation" a CEL code or something?