quick question, can you use an after market sensor because i have found one online that is quite a bit cheaper, or will this just back fire on me and not work.

has anyone used aftermarket, what has happened?

Never used an after market one, didn't even know anyone was making them? We sell brand new Ford ones and at least you will have the knowledge that it has a warranty and made in OZ.
I am guessing it is a front one? quite common on BA's

[/quote] yeah it is the front letf hand side i had it scanned by ford and they said they got it to fault once but then was all good so gave it back to me, but i got it to fault 5 minutes down the road, so now im just looking for the best price for a new sensor!