Swirl flaps

My 2008 BMW 123d recently displayed a fault code relating to the swirl flaps – I did not make a note of the exact fault. I deleted the code, expecting it to return, but it didn’t. The management light was not illuminated and there were no running problems – I was just checking my software after an update.

Having read some of the horror stories online concerning swirl flaps, I am considering removing them and replacing them with a blanking plug. Am I likely to encounter problems with the emissions or performance? Some people also mention getting fault codes registered. Martin Marsland

There are a host of codes that could be associated with the swirl flaps, but let me first put your mind at rest: the swirl flaps on your 123d are a one-piece assembly and not prone to the problems of the earlier M47TU and M57TU engines. It is very likely the code you had stored was due to swirl flap plausibility, which could have been due to a sticking motor. As the EML was not lit and this was a stored code with no problems present, it may have been a one-off occurrence.

I would monitor the situation and, if the code does return, note the actual code and let me know. I will then be able to give a more accurate diagnosis.