Lumina V6-204 3.4L DOHC VIN X SFI (1996)
Crankshaft Position Sensor: Description and Operation
Crankshaft Position (CKP) Sensor 7X
DESCRIPTION
The 7X crankshaft position sensor, a magnetic sensor, is bolted to the lower right side of the engine block. A 2-wire harness connector plugs into the
sensor, connecting it to the Ignition Control Module (ICM). The 7X sensor provides a signal - used by the ignition control module to calculate ignition
sequence. The ignition control module also uses the crankshaft position sensor signals to initiate 3X reference pulses which the PCM uses as reference to
calculate RPM and crankshaft position.
OPERATION
The 7X crankshaft position sensor is separated by an air gap from a crankshaft reluctor wheel. The crankshaft reluctor wheel, cast on the crankshaft, has
seven machined windows. Six of the machined windows are spaced at regular 60 intervals around the reluctors circumference. The seventh window is
spaced 10 from one of the other windows. As the reluctor wheel rotates with the crankshaft, the machined windows change the magnetic field generated
by the 7X crankshaft position sensor. The changed magnetic field induces a voltage signal. The ICM interprets the signal as an indication of crankshaft
position. The ICM uses the seventh window as the sync signal. To fire the correct ignition coil, the ICM must see the sync signal.
