how can i fix my renault scenic?

A very common problem I'm afraid, see BBC Watchdog:

http://www.bbc.co.uk/blogs/watchdog/2009/10/renault_get_lost_on_a_scenic_r.html

ECU Testing are probably the best place to get it repaired:

http://www.ecutesting.com/renault_megane_scenic_instrume.html

They guarantee their repairs for 2 years.

ChicksFan
May 2011