If you press Sport buttton or PSM off it doesn't do anything. What is it??

 

What do you mean "it wont go over MPH"?

 

Please help

 

Perhaps if you clarified a little, someone would be able to help. Your original title does not make sense and your post provides little additional information.

The only thing I could suggest at this point would be to remove the battery and allow it to sit for several hours to allow the cars computers to reset themselves.

 

Are you getting a beep or chime? Did you check your speed limiter or your computer?

 

Mine did something similar once. It would not go over 11 mph and had ABS/PSM lights. I had blown a hose off one of the turbos. I would check all hoses to make sure one has not come loose.

 

Just call Porsche road service that's why we pay so much for these beasts!!!