the cam sensor will not prevent the vehicle from starting. It is used for injector timing. This system uses a waste spark design that fires one plug on compression and the companion cylinder on exhaust. The ignition system doesn't care which companion cylinder is on compression. The cam sensor tells the pcm if the engine is in the first half or the second half of the firing order and fires the appropriate injector. With no input from the cam sensor, the pcm defaults to a bank fire mode that uses more fuel, but guarantees that the next cylinder to fire has fuel available. Look at the cluster when you tur the key on and see if the CEL is on. If it is, the pcm is active. if it's not, the bulb may be out or you might be loosing power or ground to the pcm. Now try to start the engine. If the light was on, and now goes out during crank, the pcm can see the engine turning over. (which means the crank sensor and wiring are ok) If the light stays on during crank, look at your crank sensor, wiring, pcm or trigger wheel.
