Crankshaft Position Sensor: Description and Operation

Crankshaft Position Sensor





The control module receives information on the position and speed of the crankshaft from the crankshaft position sensor on pin 23.

The crankshaft position sensor consists of a Hall sensor and a field rotor. The Hall sensor is fitted to the oil pump body behind the crankshaft pulley and the field rotor is mounted on the pulley itself.

The field rotor has three gaps, two large and one small. The two larger gaps begin 45°BTDC for cylinders 1+4 and cylinders 2+3. The small gap is positioned 900 before the gap for cylinders 1+4.

Engine speed signal

The control module sends out an engine speed signal on pin 29.

The signal is a pulse train which varies between 0 and battery positive (B+). Signal frequency is about 28 Hz at idling speed and about 85 Hz at 2500 rpm, which corresponds to 2 pulses per crankshaft revolution.

The engine speed signal is used by LH, ETS and the tachometer. Without an engine speed signal no fuel injection will take place.