Crankshaft Position Sensor (CKPS)

CKPS monitors engine speed and piston position. CKPS is built into into a separate sensor mounted on front of engine. CKPS has a rotor plate and a wave-forming circuit. Rotor plate has 360 small (outer) slits to determine crankshaft position (one slit for each degree of sensor rotation). Rotor plate also has 4 (4-cylinder), 6 (V6) or 8 (V8) large inner slits at 90-degree (4-cylinder), 60-degrees (V6) or 45-degree (V8) intervals to determine engine speed. Inner slit for cylinder No. 1 is wider than the other inner slits to allow ECM to determine TDC for cylinder No. 1.

The signal rotor plate passes between a Light Emitting Diode (LED) and photo diode when slits in signal rotor plate alternately cut light that is sent to photo diode from LED. This causes a pulsating voltage, which is converted into an on-off pulse by wave-forming circuit, and sent to ECM. Vehicle also has a sub-crankshaft position sensor that is used as back-up to CKPS. See SUB-CRANKSHAFT POSITION SENSOR.