ME-SFI two-sensor control function - GF07.61-P-3020AM

ENGINE 113.990 in MODEL 211, 219 

ENGINE 113.991 in MODEL 215, 220 

ENGINE 113.992 in MODEL 230 

ENGINE 113.993 in MODEL 463 

ENGINE 113.995 in MODEL 230 

Fig 1: ME-SFI Two-Sensor Control Function Diagram

The ME engine control unit determines the lambda mean value from the signals of the O₂ sensors downstream of TWC. This value is compared with a stored value for optimum exhaust emissions.

If the deviation is too large after a number of measurements, a correction variable (delay time) is determined for the lambda control. The correction variable (value for new O₂ sensor upstream TWC approx. 0) makes it possible to compensate for aging of the O₂ sensors upstream of TWC within certain limits. If the correction variable exceeds the prescribed limit value the O₂ sensors upstream of the TWC must be replaced.

The correction values are map-controlled and are implemented by the ME-SFI [ME] control unit by adapting the fuel injection.

If the limit value is exceeded or if the plausibility check on the O₂ sensor signal is negative, the engine diagnosis indicator lamp lights up in the instrument cluster or for the "CHECK ENGINE" MIL.

Exceeding a limit is stored in the fault memory and can be read out and deleted using STAR DIAGNOSIS.

The effect of the firewall catalytic converters is also monitored based on the O₂ sensor signals downstream of the TWC.

	Fuel injection valve - location/task/design/function		GF07.03-P-5004KE
	O2 sensors - location/task/design/function		GF07.04-P-4103AM
	ME-SFI control unit - location/task/design/function		GF07.61-P-5000AM
	Exhaust system - location/task/design/function		GF49.00-P-2000AM
	Three-way catalytic converter - location/task/design/function		GF49.10-P-3002AM
	"CHECK ENGINE" MIL - location/task/function	for	GF54.30-P-4101AM
	Engine diagnosis malfunction indicator lamp - location/task/function	except	GF54.30-P-4102AM