[ITSv40]

'er indoors Mini Cooper threw a eml light, changed the lambda sensors, light back on after a while. Checked for manifold and exhaust leaks, threw two lots of Cataclean through it and light still came on intermittently. Read up on the net and consensus was: once the light starts to come on impossible to rectify. My son connected up the proper BMW diagnostics and immediately it said Cat f******* change cat. £1200 later the new genuine cat has solved the issue and car is now running better then before. When I removed the old one the core had come loose and clogged the outlet pipe. I suspect yours needs a new cat or a good secondhand.