Grand Caravan FWD V6-3.3L VIN 3 Flex Fuel (2002)
Fig.1 Camshaft Position Sensor
Fig.2 Camshaft Sprocket
The camshaft position sensor provides cylinder identification to the Powertrain Control Module (PCM). The sensor generates pulses as groups of
notches on the camshaft sprocket pass underneath it. The PCM keeps track of crankshaft rotation and identifies each cylinder by the pulses generated by
the notches on the camshaft sprocket. Four crankshaft pulses follow each group of camshaft pulses.
When the PCM receives 2 cam pulses followed by the long flat spot on the camshaft sprocket, it knows that the crankshaft timing marks for cylinder 1
are next (on driveplate). When the PCM receives one camshaft pulse after the long flat spot on the sprocket, cylinder number 2 crankshaft timing marks
are next. After 3 camshaft pulses, the PCM knows cylinder 4 crankshaft timing marks follow. One camshaft pulse after the 3 pulses indicates cylinder 5.
The 2 camshaft pulses after cylinder 5 signals cylinder 6. The PCM can synchronize on cylinders 1 or 4.
When metal aligns with the sensor, voltage goes low (less than 0.3 volts). When a notch aligns with the sensor, voltage switches high (5.0 volts). As a
group of notches pass under the sensor, the voltage switches from low (metal) to high (notch) then back to low. The number of notches determine the
amount of pulses. If available, an oscilloscope can display the square wave patterns of each timing event.
