Theory Of Operation

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

The Crankshaft Position (CKP) Sensor circuits consist of a Powertrain Control Module (PCM) supplied 5-Volt reference circuit, low reference circuit and an output signal circuit. The CKP Sensor is an internally magnetic biased digital output integrated circuit sensing device. The sensor detects magnetic flux changes between the peaks and valleys of a tone wheel on the crankshaft. Each tooth on the tone wheel is evenly spaced with missing teeth used as a reference gap. The CKP Sensor produces an ON/OFF DC voltage of varying frequency, reference output pulses per crankshaft revolution. The frequency of the CKP Sensor output depends on the velocity of the crankshaft. The CKP Sensor sends a digital signal to the PCM, which represents an image of the crankshaft tone wheel. The PCM uses each CKP signal pulse to determine crankshaft speed and decodes the crankshaft tone wheel reference gap to identify crankshaft position. This information is then used to sequence the ignition timing and fuel injection events for the engine. The PCM also uses CKP Sensor output information to determine the crankshaft position relative to the camshaft. This information is used to identify cylinder misfires and to control the CMP actuator if equipped.