<strong>Crank Position Sensor (CPS)</strong><br />Also known as the crank position sensor, this one is important. OK, all the sensors are important, but this one possibly the most. It is located on the bellhousing near the engine either at the 11 o'clock position or the 3 o'clock position. Without signal from this, the Jeep just won't run. That means if there is a short in the wire, it will die. If you unplug your buddy's CPS, his Jeep will never start. It senses (as the name implies) the position of the crankshaft and allows the engine computer to figure out when to fire the spark plugs and simply let it know it's running.