Crankshaft Position Sensor: Description and Operation

Fig. 7 Crankshaft position sensor. 1.3L/4-80.8 & 1.8L/4-109 engines:

PURPOSE
The Crankshaft Position Sensor (CPS) provides crankshaft rotation speed input to the ECA. The ECA uses this signal to modify air/fuel ratio, idle speed, injector timing, ignition timing, purge flow, A/C cutoff and air inlet control.

OPERATION
The sensor consists of a disc with 4 equally spaced slots and a photo sensor. As the disc rotates with the distributor shaft, each slot passes through the fixed photo sensor. The sensor senses the slots and sends a signal to the ECA reflecting crankshaft rotation speed.