GM Service Manual Online
For 1990-2009 cars only

The two crankshaft sensors are located on the front bank of the engine block between cylinders 4 and 6. Crankshaft position A sensor is located in the upper crankcase and crankshaft position B is located in the lower crankcase. Both sensors extend into the crankcase and are sealed to the engine block with O-rings.

The magnetic crankshaft position sensors operate similar to the pick-up coil in a destributor. When a reluctor is repeatedly moved out the sensor, a voltage will be created by the sensor that appears to go ON-OFF-ON-OFF-ON-OFF. This signal is also similar to the signal that a set of breaker points in a distributor would generate as the distributor shaft turned and the points opened and closed.

The crankshaft sensors are not adjustable. For on-vehicle service, refer to Crankshaft Position (CKP) Sensor Replacement .