Park Avenue V6-3.8L SC VIN 1 (2005)
Crankshaft Position Sensor: Description and Operation
CRANKSHAFT POSITION (CKP) SENSORS
The crankshaft position (CKP) sensor has a 4-wire harness connector that plugs into the CKP sensor and connects to the ignition control module (ICM).
The CKP sensor contains 2 hall-effect switches in 1 housing, and shares a magnet between the switches. The magnet and each hall-effect switch are
separated by an air gap. A hall-effect switch is a solid state switching device that produces a digital ON/OFF pulse when a rotating element passes the
sensor pick-up and interrupts the magnetic field of the sensor. The rotating element is called an interrupter ring or blade. There are two interrupter rings
built into the crankshaft balancer. The outer ring and the outer switch provide the ICM with 18X signals or 18 identical pulses per crankshaft revolution.
The inner ring and the inner switch provide the ICM with 3 pulses per revolution, each 1 of different duration. This is called the sync pulse. Each sync
pulse represents a pair of companion cylinders. The ICM supplies a 12-volt and a low reference circuit to the CKP sensor, which is also shared by the
camshaft position (CMP) sensor. The 18X reference pulses are passed from the CKP sensor to the ICM on the CKP sensor 1 signal circuit. The sync
pulses are passed from the CKP sensor to the ICM on the CKP sensor 2 signal circuit. The ICM uses the 18X and sync pulses to determine the crankshaft
position by counting how many ON-OFF 18X pulses occur during a sync pulse. With this dual interrupter ring arrangement the ICM can identify the
correct pair of cylinders to fire within as little as 120 degrees of crankshaft rotation.
CRANKSHAFT BALANCE INTERRUPTER RING
Each interrupter ring has blades and windows that either block the magnetic field or allow it to close one of the hall-effect switches. The outer hall-effect
switch sends a pulse called the 18X reference signal. The outer interrupter ring has 18 evenly spaced blades and windows. The 18X reference signal
produces 18 ON-OFF pulses per crankshaft revolution. The inner hall-effect switch sends a pulse called the sync signal. The inner interrupter ring has 3
unevenly spaced blades and windows of different widths. The sync signal produces 3 different length ON-OFF pulses per crankshaft revolution. When
the sync interrupter ring window is between the magnet and the inner switch, the magnetic field will cause the sync hall-effect switch to ground the
supplied voltage from the ICM. The 18X interrupter ring and the hall-effect switch react similarly.
