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

ENGINE 272.911 in MODEL 204.0 up to Model Year 08

ENGINE 272.921 in MODEL 204.0/2 up to Model Year 08

ENGINE 272.947 in MODEL 204.0/2 up to Model Year 08

ENGINE 272.948 in MODEL 204.0 up to Model Year 08

ENGINE 272.961 in MODEL 204.0/2 up to Model Year 08

ENGINE 272.971 in MODEL 204.0 up to Model Year 08

Fig 1: ME Engine Speed Signal Diagram

Courtesy of MERCEDES-BENZ USA

Based on signals from the crankshaft Hall sensor (B70), the short circuit-proof engine speed signal "TNA" is generated in the ME-SFI [ME] control unit (N3/10) and forwarded to other control units via the CAN data bus.

The engine speed signal "TNA" is a square-wave signal with a constant on/off ratio of 6 pulses per engine revolution (a 60° CA) and a maximum current of approx. 20 mA.

The voltage signal (AC voltage) is generated by webs on the increment wheel (perforated plate) in the crankshaft Hall sensor by the turning crankshaft. Each web generates a voltage signal. No signal voltage is generated as a result of the gap created by 2 missing webs.

If the voltage signal from the crankshaft Hall sensor is missing, voltage signals from the left and right intake camshaft Hall sensor (B6/4, B6/5) or from the left and right exhaust camshaft Hall sensor (B6/6, B6/7) are used as a substitute (for limp-home).

The engine speed signal is readable on the diagnostic connector (X11/4) with any commercially available diagnostic equipment.

	Component description for the crankshaft Hall sensor	B70	GF07.04-P-6221CY
	Component description for the ME-SFI [ME] control unit	N3/10	GF07.61-P-6000CY