Dash warning light

[GHunter2]

Hi

I have a warning light on my dash, I have tried replacing the lambda sensor but no luck sorting it

My mechanic hooked up a diagnostic machine and thinks it is a heat sensor causing the problem

I can't seem to find these to buy anywhere, has anyone had this problem and know where to buy one?

Thanks

[alexperkins]

What's the fault code it's getting (normally starts withal a P)