Crankshaft Position Sensor: Description and Operation

Distributor:

PURPOSE
Provides engine speed and crankshaft position information to the Engine Control Module (ECM).

LOCATION
Built into distributor.

OPERATION AND CONSTRUCTION
Built into the distributor, the crankshaft position (CKP) sensor consists of a photoelectric pick-up and rotor plate with light transmission slits. As the rotor plate turns, the slits alternately transmit and cut light read by the photoelectric pick-up unit. This generates pulses utilized by the ECM to calculate engine rpm and crankshaft position.

This generates pulses utilized by the ECM to calculate engine rpm and crankshaft position.

The ECM uses the input from the crankshaft position (CKP) sensor, together with information from other sensors, to calculate and control the ignition timing advance curve.

Other sensors whose input is factored into ECM timing calculations include:
- Throttle valve switch
- Vehicle speed sensor
- Coolant temperature sensor
- Air flow sensor