[matoneski]

Hi,

I have a 2020 m135i stage 2 with a high-flow cat downpipe. The Check Engine Light (CEL) keeps coming back on. Has anyone else had an issue like this?

Side note, there is a strange fluttering/ticking noise that increases with acceleration and under boost from 3k revs. It only makes the noise when moving. Any ideas on that would also be appreciated.

Thanks,

[rossm]

You need a Femto unlock and proper ECU remap. Your car is likely running very lean and will cause damage if you don't. I would suggest you should put the cat back on

The ticking noise is likely to be turbo wastegate, you may get it sorted under warranty, but only after you put the cat back and hope BMW don't flag it due to the CEL, some fault codes cant be overwritten.

[Jay Ell]

Originally Posted by matoneski

Hi,

I have a 2020 m135i stage 2 with a high-flow cat downpipe. The Check Engine Light (CEL) keeps coming back on. Has anyone else had an issue like this?

Side note, there is a strange fluttering/ticking noise that increases with acceleration and under boost from 3k revs. It only makes the noise when moving. Any ideas on that would also be appreciated.

Thanks,

the fluttering is the wastegate yes.. however, having fought with my dealer and won in that they agreed the noise wasn't right and eventually took the car back with full refund. I then bought another M135i thinking it was just my car. Nope, they all seem to do it.

[a8rt]

I also have the same issue with my 118i with my 03/23 software update. Previously it was fine.