Crankshaft Position Sensor

The 2.2L, 3.1L and 4.6L Direct Ignition System (DIS) and the 2.4L Integrated Direct Ignition (IDI) system Crankshaft Position (CKP) sensor is a 2-wire, Permanent Magnet (PM) generator which protrudes through the side of the engine block to within .050" (1.3 mm) of an internally-mounted crankshaft reluctor ring. The reluctor ring is a special trigger wheel (notches) cast into the crankshaft. An extra notch in the reluctor ring delineates TDC for cylinder No. 1. As crankshaft rotates, notches in reluctor ring change the magnetic field at the tip of the CKP sensor. This creates an induced AC voltage signal in the sensor windings, resulting in reference signals which are sent to PCM by ignition control module. This allows PCM to compute crankshaft position and RPM and fire appropriate ignition coil at the proper time. On 3.1L, an additional crankshaft signal is generated by a 24X Hall Effect sensor.

On 3.5L, CKP sensor is actually 2 sensors within a single housing. Each sensor has a separate power, ground and signal circuit. The PCM supplies 12 volts and a ground path to both sensors and are also connected to Camshaft Position (CMP) sensor. Two separate signal circuits connect the CKP sensor to the PCM.

The PCM can use 3 different modes of decoding crankshaft position. During normal operation, the PCM performs an Angle Based calculation using both signals to determine crankshaft position. The dual sensor allows the engine to run even if one signal is lost. If either signal is lost, the PCM switches to a Time Based method of calculating crankshaft position. If system operates in Time "A" mode, PCM uses only the signal from sensor "A". Time "B" mode indicates that sensor "B" signal is being used. If the lost signal is restored, PCM will continue to operate in Time Based mode until the next key cycle. PCM reverts back to Angle Mode on the next key start if fault is no longer present. A fault in sensor "A" will set a different trouble code than sensor "B".

On 3.8L, CKP sensor utilizes a 4-wire dual Hall Effect switch mounted near vibration damper. Sensor monitors vibration damper position (crankshaft position) and sends signals to ignition control module, which passes these signals on to the PCM. These signals provide PCM with a TDC position reference for each piston, as well as supplying an engine speed (RPM) signal.