Camshaft Position Sensor (HEI)

The 4.9L engine uses a Hall Effect camshaft sensor located inside the HEI distributor. The cam sensor provides PCM with a TDC No. 1 signal used to compute the exact position of valves. This allows PCM to properly time ignition and fuel injection. A fault in the cam sensor circuit (no cam sensor signal) will result in a no-start condition (except 4.9L) and should set a related trouble code. For additional information, see HEI-EST DISTRIBUTOR  under IGNITION SYSTEM.