I have an '03 Cooper S that has gone into "limp home" mode just after I pass 5K RPMs. I restart the car and it runs fine and the SES light clears after 5 key turns, however, this is well under the redline limit. I was wondering if anyone else has experienced something similar. I am currently trying to call a service advisor. I plan to take the car in this weekend--I have just under 2 mos. left on my warranty, so obviously I am going to take advantage of that while I can.

 

most definitely your bypass valve, do a search, a lot of threads for the same issue or similar. good luck!

 

Thanks for the input. I have a Monday morning appt. I will post the verdict when it's sorted out. For now, the car is still driveable, but for obvious reasons, I am keeping RPMs on the low side.

 

Verdict: Supercharger bypass valve. I also had them look at my driver side window, and that will be getting a new motor as well (it tends to stick in warmer weather and I can't open the window). The service advisor tried to stick me with new tires, but I think I will order non runflats online and get a can of fix-a-flat. At 31+K miles, I think I have gotten my money's worth from the original runflats.

 

I had pretty much the same experience today. As I said in my own thread, I was able to get it unstuck just by pushing on the external part that rotates. No biggie. But for future reference, you may want to look at your bypass valve and understand how it works so you can try and get it unstuck
if you want, rather than taking it to the dealer. I found the best pictures of it so far in the vacuum gain system thread.