Crankshaft Position Sensor: Description and Operation

Crankshaft Position (CKP) Sensor:

DESCRIPTION

The Crankshaft Position (CKP) sensor provides a signal to the electronic Ignition Control Module (ICM), which the PCM uses as a reference to calculate RPM and crankshaft position.


OPERATION

The Crankshaft Position (CKP) Sensor This system uses a magnetic CKP sensor (2), mounted remotely from the ICM (3), which protrudes into the block within approximately 0.050 inches from the crankshaft reluctor (1). The graphic illustrates a typical sensor in relationship to the crankshaft reluctor. The reluctor is a special wheel which is cast into the crankshaft with 7 slots machined into the wheel, 6 of which are equally spaced (60 degrees apart). A seventh slot is spaced 10 degrees from one of the other slots and serves to generate sync-pules. As the reluctor rotates as part of the crankshaft, the slots change the magnetic field of the sensor, creating an induced voltage pules. Based on the CKP sensor pules, the CKP sensor sends a 7x reference signal to the PCM which is used to indicate the crankshaft position and the engine speed. The CKP sensor continues to send these reference pulses to the PCM at a rate of seven times per 360 degrees of crankshaft revolution. This signal is called the 7x reference because the signal occurs 7 times per crankshaft revolution. The 7x reference signal is necessary in order for the PCM to determine when to energize the fuel injectors.


CIRCUIT FAULTS

A fault in the CKP sensor circuits will cause a DTC P0335.

Important A Crankshaft Position System Variation Learning Procedure must be performed any time a change is made to the crankshaft sensor to crankshaft relationship. Changing the crankshaft sensor to crankshaft relationship will not allow the PCM to detect misfire at all speeds and loads accurately. Resulting in a possible false misfire DTC being set. Removing a part for inspection and then reinstalling the same part is considered a disturbance. A false DTC P0300 could be set if this procedure is not performed. Refer to the CKP Sensor Service and Repair for the Crankshaft Position System Variation Learning Procedure.