"Cam Position Sensor
The CMP scans a reference cam on the camshaft. The CMP sends an alternating voltage signal to the PCM. This indicates the firing position of No1 cylinder. This is only used when starting starting. after that the (PIP) signal takes over to control the injectors.

Crankshaft Position Sensor
The CKP sensor is also an inductive pulse generator, like the CMP which scans 36 minus 1 cast protrusions on the flywheel. Minus one means that one of the protrusions is missing. This missing protrusion is located at 90º before top dead center and is used by the powertrain control module as a reference mark for the crankshaft position. The crankshaft position sensor sends an alternating voltage signal to the powertrain control module, which is used to determine engine speed and ignition timing."