Crankshaft position sensor function - GF07.04-P-4116-01M

Crankshaft position and engine speed are detected without contact. The clearance between crankshaft position sensor (L5) and the teeth (d) of the drive plate (incremental gear) is fixed by the installation position (approx. 0.8 mm).

When the crankshaft is rotating, an alternating voltage is generated (induced) in the crankshaft position sensor by the teeth of the driven plate.

Fig 1: Identifying Crankshaft Position Sensor With Missing And Incremental Gear Teeth Of Driven Plate

Courtesy of MERCEDES-BENZ USA

Fig 2: Identifying Signal Of Crankshaft Position Sensor

Courtesy of MERCEDES-BENZ USA

The leading edge of a tooth (a) generates a positive voltage pulse and the trailing edge (b) a negative voltage pulse. The distance from the positive to the negative voltage peak corresponds to the length of a tooth.

The gap produced by 2 missing teeth (c) results in no voltage being generated in the crankshaft position sensor (L5). This point serves for detecting the TDC position of cylinder 1 and 7.