it tells the ECU the position of the camshaft, i.e which stroke it is on such as intake/exhaust etc... cam position is important for the ECU to know when to inject fuel.
If the camshaft is out then the output from the sensor still shows as correct, hence no fault code. but cam timing is out so valves are opening/closing at the wrong time.
Thanks for that Dave
do i take it this sensor just runs off the intake cam?
my exhaust popped and banged for ever when my timing was out and also my car ran rich with the timing being pulled , my fuel consumption was utter crap , since the timing has been put right fuel is good about 50 more miles to a tank no more popping
and importantly no missfires (touch wood)
Where my timing was out my intake valves looked like detonation was occuring and leaking back behind the valve heads leaving a ring of caked on crap around the valve seat.
Also i had the same overuse of silicone sealent and oil leaks from the head
