how do i find and exchange cam sensor on my vauxhall vectra 18 16v etec engine 1999.. as missing at 1900 revs and 2100, and only ticking over at 200 in mornings etc, had new loom, and cam belt etc , new air sensor,throttle housing , dci pack , new plugs , etc ect and engine mananger ment light still comes on ... with fault idle air control circuit voltage high,, can u help please ... thanks

steve, July 2007

Not sure that your fault is the cam sensor, but here's how you change it:

1. Remove the air cleaner and the rubber inlet hose up to the joint after the MAF sensor.
2. Remove the engine front stabiliser (15mm & 16mm bolts). There is no need to support the engine.
3. Remove the driver's front road wheel.
4. Using a 15mm socket on a ratchet, release the V belt tensioner and unhook the belt off the alternator pulley.
5. Remove the cam belt cover (3 x 10mm bolts). Do not loose the plastic inserts!
6. Carefully manoeuvre the cover off.
7. Using a suitable socket remove the small torx bolt securing the cam sensor in place. The sensor then lifts out vertically.
8. Fitting is the reversal of removal. Before doing so you might want to check the condition and tension in the cam belt. The tension is indicated by a pointer on the belt tensioner. It should be aligned with either the left hand mark (used belt) or the right hand mark (new belt). Check that the water pump is not leaking and that the pump bearing is not badly worn.
9. After reassembly the engine should run and the warning light will be off. The fault code will still be logged in the ECU and can be removed with a Tech-2 type OBD reader. This is not essential for the repair to take effect. It is an urban myth that the code must be cleared as well as fixing the fault for the warning light to go out!

Kevin, October 2007