Crankshaft Position (CKP) Sensor System

The 18x Crankshaft Position (CKP) sensor contains two hall-effect switches in one housing. A hall-effect switch is a solid state switching device, which produces an ON-OFF pulse when a rotating element passes the sensor pick-up and interrupts the magnetic field. The rotating element is called an interrupter ring or blade. In this case there are two interrupter rings built into the crankshaft balancer. The outer ring and outer switch provides the PCM with the 18x signals, or 18 pulses per crankshaft revolution. The inner ring and inner switch provide the PCM with a sync pulse three times per crankshaft revolution. The IC module uses the 18x and sync pulses to determine the engine position, by counting how many ON-OFF 18x pulses occur during a given sync pulse. Each of the 3 sync pulses represent a pair of cylinders both at top dead center at the same time, which are called companion cylinders. With this dual interrupter ring arrangement the IC module can identify the correct pair of cylinders to fire within as little as 120 degrees of crankshaft rotation.