yer 99% sure it will be your decat! mine came on with a sports cat:dapprove:
I've got a sports CAT on mine and the light comes on every few thousand miles or so. Seems to come on far more frequently when cruising long distance with the cruise control on.
Got a hand held code reader from K-Tec - kinda paid for itself already as I've used it 5 or 6 times and Renault would no doubt charge a fortune for a reset.....
http://www.k-tecracing.com/show_product.asp?id=2400
Does this mean if the cat is still fitted and the light comes on, your cat is buggered? Or is it more likely the lambda sensor has failed.
I have this problem at the moment, but it came on with the standard exhaust in place
Thanks