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Component description for crankshaft Hall sensor - GF07.04-P-6220V

ENGINE 272.942 in MODEL 171 

ENGINE 272.963 in MODEL 171 

Location 

The crankshaft Hall sensor is located behind the left cylinder bank.

Fig 1: Identifying Crankshaft Hall Sensor Components - Engine 272.920/940/941/960/970
G04736595Courtesy of MERCEDES-BENZ USA

Task 

It detects the engine speed and the crankshaft position by scanning a perforated plate welded to the starter ring gear (incremental wheel).

Design 

Hall sensor in plastic housing with 3-pole plug connection, distance from the increment wheel 0.3 to 1.3 mm.

Function 

The crankshaft Hall sensor scans the increment wheel at the starter ring gear. The increment wheel has 58 links and a gap, at which two links are missing (60-2).

Each 4 mm wide link generates a signal change at the crankshaft Hall sensor. The signal changes in the link center from around 5 V to around 0 V (negative signal edge).

No signal change takes place at the gap with the 2 missing links. The ME-SFI [ME] control unit detects the TDC position of cylinder 1 with the 2nd negative flank after the gap.

In the ignition TDC of cylinder 1, the signals from the camshaft Hall sensor are also "LOW".

Fig 2: Identifying Crankshaft Hall Sensor And Increment Wheel - Engine 272.920/940/941/960/970
G04736596Courtesy of MERCEDES-BENZ USA

IMPORTANT

Only the negative signal edge of the crankshaft Hall sensor signal is ever evaluated. For example, for a frequency measurement, the gap between two negative edges must be measured.

The rising negative edge of the signals occurs when a window is located opposite the crankshaft Hall sensor (no material). At the wide gap in particular, the signal fluctuates greatly and is therefore not used.

Shown on engine 272 

Fig 3: Identifying Crankshaft Hall Sensor Signal Pattern - Shown On Engine 272
G04736597Courtesy of MERCEDES-BENZ USA

Shown on engine 273 

Fig 4: Identifying Crankshaft Hall Sensor Signal Pattern - Shown On Engine 273
G04736598Courtesy of MERCEDES-BENZ USA