I had a random CEL come on in my car (the car would go into safe mode and shutdown a cylinder) and with all the mods I have done to the engine (15%, Alta CAI, Milltek cat-back) the dealer decided upgrading my car with JCW software would fix it (nothing else could be found). After the JCW, I added the standard MTH software. Will the MTH overwrite the JCW the dealer installed? I am taking my mini in this week to fix another CEL (it comes on randomly, but no change to anything else ie. shutting down cylinders) I am thinking of switching the car to pre-MTH, but want to make sure what they will see/possibly erase if they upgrade the s/w.

Thanks!

phil.

 

MTh overrides JCW and visa versa. BMW SW upgrade does the same thing.