G6 L4-2.4L VIN B (2006)
Crankshaft Position Sensor: Description and Operation
CRANKSHAFT POSITION (CKP) SENSOR
The crankshaft position (CKP) sensor is a permanent magnet generator known as a variable reluctance sensor. The CKP sensor produces an AC voltage
of varying amplitude and frequency. The frequency depends on the velocity of the crankshaft. The AC output depends on the crankshaft position and the
battery voltage. The CKP sensor works in conjunction with a 58-tooth reluctor wheel attached to the crankshaft. As each reluctor wheel tooth rotates past
the CKP sensor, the resulting change in the magnetic field creates an ON/OFF pulse 58 times per crankshaft revolution. The engine control module
(ECM) processes the pulses to create a pattern that enables the ECM to determine the crankshaft position. The ECM can synchronize the ignition timing,
the fuel injector timing, and the spark knock control based on the CKP sensor and the camshaft position (CMP) sensor inputs. The CKP sensor is also
used to detect misfire and for tachometer display. The ECM learns the variations between all 58 teeth under different speed and load conditions to
correctly detect misfires. The CKP sensor circuits consist of a signal circuit, an ignition 1 voltage circuit, and a low reference circuit. The two wires are
twisted together to prevent electromagnetic interference on the CKP sensor circuits.
