Crankshaft Position Sensor: Description and Operation

Crankshaft Position Sensor (L5/4 And L5/5) Location:

PURPOSE AND LOCATION
The two crankshaft position sensors (L5/4 and L5/5) register the crankshaft position and engine speed. The position sensors are mounted to the engine block behind the cylinder heads. The sensor body projects through the engine block very near to the segments on the flywheel/drive plate. There is no contact between the segments or the position sensor.





OPERATION
With the engine running, the three segments pass by the position sensor. Due to induction, an alternating voltage is generated in the position sensor. The peak voltage is approx. 1.5 volts at starting speed. The voltage rises with increasing speed to approx. 3 volts at 1200 rpm.

Crankshaft Position Sensor (L5) Signal:

t1 = First Segment
t2 = Second Segment
t3 = Third Segment
d = Period for one crankshaft rotation

The crankshaft position is recognized from the voltage signals which are produced. The segment front edge generates a negative voltage signal. The segment rear edge generates a positive voltage signal. Engine speed is determined by measuring the period (d) which is equal to one crankshaft revolution.

SIGNAL
This AC voltage signal is used by the EZL/AKR control modules and transmitted via the controller area network (CAN) to the LH control modules.