Crankshaft Position Sensor: Description and Operation

Crankshaft Position Sensor:

DESCRIPTION
The Crankshaft Position (CKP) sensor works in conjunction with a 58 tooth reluctor wheel on the crankshaft. The ECM pulls up the CKP sensor signal circuit to 12 volts and monitors this voltage. As each reluctor wheel tooth rotates past the sensor, the sensor's internal circuitry pulls the signal circuit to ground, creating a square wave signal used by the ECM. The reluctor wheel teeth are 6 degrees apart. Having only 58 teeth leaves a 12 degree span that is uncut. This creates a signature pattern that enables the ECM to determine the crankshaft position.

OPERATION
The ECM can determine which two cylinders are approaching the top dead center based on the CKP signal alone. The Camshaft Position (CMP) sensor signal is used in order to determine which of the two cylinders is on a firing stroke. The ECM can then properly synchronize the ignition system, the fuel injectors and the knock control. This sensor is also used to detect a misfire. Refer to DTC P0300 for information on misfire detection.

Circuit Malfunctions
The ECM also monitors the CKP sensor system for malfunctions. The following DTCs indicate that the ECM has detected a CKP system problem:

^ DTC P0335 - CKP Sensor Circuit
^ DTC P0336 - CKP Sensor System Performance