Crankshaft Position Sensor: Description and Operation

PURPOSE
The Crankshaft Position (CKP) sensor provides base timing and engine speed information to the Ignition Control Module (ICM). The ICM supplies this information to the Powertrain Control Module (PCM) as the Profile Ignition Pickup (PIP) signal. The PCM uses this information for fuel injector timing and calculating ignition timing advance and dwell.

CONSTRUCTION
The CKP is a variable reluctance type sensor that monitors the movement of a 35 tooth wheel located behind the crankshaft pulley.

EI Ignition System Oscilloscope Waveform:

OPERATION
As the teeth on the crankshaft pass by the CKP a voltage is induced in the sensor. The CKP output is a spiked sine wave that is proportional to crankshaft speed and position. The missing tooth (36 minus 1) design allows the ICM to synchronize the signal and select the correct coil to fire.