Hi everybody,

I am a new user in this forum.
I am a owner for five years of a very nice but with a big 200k RS2 slightly modified at Seymaz Racing (Switzeland)
Now, I do have a starting problem with the car.
I changed with a new and more powerful battery but no result !
After a BOSCH diagnostic, I got those messages :
- Engine calculator to check. Default : 0201 Speed sensor no signal / sensor of ref. for circuit.
What does this last message means ?

Could someone advise me about what could be the origin of this problem and how to overcome it ?
Thanks and bye.