TrailBlazer 4WD L6-4.2L VIN S (2002)
Crankshaft Position Sensor: Description and Operation
The crankshaft position (CKP) sensor is a permanent magnet generator, known as a variable reluctance sensor. The magnetic field of the sensor is
altered by a crankshaft mounted reluctor wheel that has seven machined slots, six of which are equally spaced 60 degrees apart. The seventh slot is
spaced 10 degrees after one of the 60 degree slots. The CKP sensor produces seven pulses for each revolution of the crankshaft. The pulse from the 10
degree slot is known as the sync pulse. The sync pulse is used to synchronize the coil firing sequence with the crankshaft position. The CKP sensor is
connected to the PCM by a signal circuit and a low reference circuit.