The crankshaft sensor on the Chevrolet Cavalier 2.4 is located in the middle of the side of the block, just above the oil pan and above the oil filter. It provides a signal through the ignition module, which the computer then uses as a reference to calculate the position of the crankshaft and engine rpm. The vehicle will usually run if the crankshaft position sensor malfunctions, but it will run poorly. The Cavalier may or may not start once you shut it off after the sensor malfunctions.
Remove the negative battery cable and set it aside, ensuring that it doesn't touch metal. Raise the vehicle, using the floor jack, then support it with jack stands.
Unplug the wiring harness connector by pulling the tabs away from the plug, then pulling the plug off the sensor. Remove the retaining bolt, then pull the sensor off the engine.
Lubricate the new O-ring with engine oil, then slide it on the sensor. Reinstall the sensor and tighten the retaining bolt firmly. Plug in the wiring harness connector. Lower the vehicle off the jack stands using the floor jack. Reconnect the negative battery cable.
