Camshaft Position Sensor: Description and Operation

Camshaft Position Sensors

The Camshaft Position (CMP) sensor is a Hall style pickup that senses a toothed camshaft reluctor wheel. The number of teeth will vary with engine combinations, but the main purpose is to provide a cylinder 1 Top Dead Center (TDC) after the compression stroke and to reference the camshaft position for proper timing of the camshaft advance mechanism. There will be one sensor ( camshaft position sensor (G40) ) on engines that use no camshaft adjuster or only an intake camshaft adjuster, and two camshaft position sensors ( camshaft position sensor (G40) and camshaft position sensor 2 (G163) ) for engines which have an adjuster on the intake and exhaust camshafts. The waveform is a square wave similar to the engine speed sensor, but may have less waves in sequence because of the lower number of teeth and wider spacing on the reluctor. If the camshaft position signal is lost, camshaft advance/retard features will be disables along with affecting sequential injection and knock retard control.