Crankshaft Position (CKP) Sensor
Crankshaft Position (CKP) Sensor:
The Crankshaft Position Sensor (CKP) is located underneath and slightly to the left of the oil filter housing. The CKP sensor produces an AC voltage of different amplitude and frequency depending on the velocity of the crankshaft reluctor wheel. The crankshaft reluctor wheel contains 58 teeth that are 6 degrees apart with a 12 degree span that is uncut. This 12 degree span is used to locate the cylinder #1 top dead center piston position used for engine synchronization. The CKP sensor in conjuction with the camshaft position (CMP) sensor can properly synchronize spark timing; fuel timing and spark knock control.
The large numbers of teeth on the reluctor wheel are used to correctly detect engine misfires. The ECM automatically learns the variation between all of the 58 teeth under 24 different engine speed/load ranges. To correct detect misfires, the ECM will monitor the time it takes to pass 20 of the teeth (120 degrees of crankshaft rotation) after a cylinder has fired. If the time (based on engine speed and load) to pass the 20 teeth is too long, a cylinder misfire has occurred.