if its the cam sensor it measures the cam shaft speed compared to the crankshaft speed. i dont think it affects the running of the car but will put the light on. i dont thikn they are to exspensive but if you do replace it put a genuine vauxhall 1 on because i have had trouble with after market ones at work.

Thhe crank rotation sensor pics up the crnak position, and it's in one of two positions, up and down (relative to piston no1) so the engine managment can't tell if it's no1 or 4 that's firing on that stroke.

the cam sensor can identifiy which cylinder is firing, this allows sequential fuel injector firing.

you mean crankshaft sensor ???

I stops the engine firing the injectors sequentially, and they turn to batch fire reducint effeincty of the engine.

car runs fine it comes on when im driving around - it pishes me off.

wat does it affect - obvously cam shafts but what sre the camshafts

i sound well thick i bet!!

unplug it and if the car stays the same I guess its not running right then its the cam shaft sensor

what is this and what does it do and if its broke is it a big problem??

thanks, sorry 4 bluntness:P