The crankshaft position sensor has a number of tasks, which include determining the ignition and fuel injection timing for each cylinder and detecting the engine's RPM. If the sensor does not send input to the Powertrain Control Module, the engine will not run. If you need to replace the crankshaft position sensor on your Jeep Liberty, you need to know its position on the engine. In most cases, the sensor is on the right side of the engine block near the front engine mount for a four-cylinder engine; on a V6, it is near the rear of the engine on the right side of the engine bedplate.
Disconnect the electrical connector for the sensor. Disconnecting the negative battery cable first is a good precaution.
Remove the crankshaft sensor's lone mounting bolt with a wrench and then carefully twist the crankshaft sensor to remove it from the engine. Remove and discard the O-ring.
Lubricate the new O-ring with a small amount of fresh engine oil and install the ring onto the replacement crankshaft sensor.
Push the crankshaft position sensor into place on the engine block until it is fully seated and then install the mounting bolt. If you have a torque wrench, most Liberty vehicles require the bolt torqued at 21 foot-pounds.
Reconnect the electrical connector to the crankshaft sensor, then reconnect the negative battery cable if you disconnected it, tightening the cable's clamp nut with the wrench.