ME-SFI engine speed signal, function - GF07.61-P-3017G

ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08

Function requirements for the engine speed signal for the ME gasoline injection and ignition system (motor electronics) (ME), general points

Circuit 87M ON (engine control ON)
Engine running

ME-SFI engine speed signal, function sequence

Using the signal from the crankshaft Hall sensor (B70), the ME-SFI [ME] control unit (N3/10) generates the short-circuit-proof engine speed signal (TN) (e.g. for mechanical testing and diagnosis) and sends it as a direct signal.

A voltage pulse (AC voltage) is generated in the crankshaft Hall sensor by the stays on the increment wheel (perforated plate) for a turning crankshaft. Here, each tooth generates a voltage pulse. No voltage is generated at the gap where there are 2 missing teeth.

The engine speed signal is a square wave signal with a constant duty cycle of six pulses per engine revolution (a 60° crank angle (KW)) and a maximum current about I = 20 mA.

If the voltage pulse from the crankshaft Hall sensor fails the voltage pulses from the following sensors are used as a substitute (for limp-home mode):

LH intake camshaft Hall sensor (B6/4)
RH intake camshaft Hall sensor (B6/5)
LH exhaust camshaft Hall sensor (B6/6)
RH exhaust camshaft Hall sensor (B6/7)

The engine speed signal can be read out at the data link connector (X11/4) using commercially available diagnostic units.

Signal assignment

Fig 1: Identifying ME-SFI Engine Speed Signal Chart

Courtesy of MERCEDES-BENZ USA

Component description for ME-SFI [ME] control unit

N3/10

GF07.61-P-6000G