GF07.61-P-3020AMG ME-SFI Two-Sensor Control, Function

GF07.61-P-3020AMG ME-SFI Two-Sensor Control, Function







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 sensor upstream of TWC within certain limits. If the correction variable exceeds the limit value, the O2 sensor upstream of 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.

Two sensor control is only enabled when the catalytic convertors have reached their operating temperature and the O2 sensors downstream TWC operate correctly.

If limit values are exceeded, or if the plausibility check of the O2 sensor signal is negative, a fault is stored in the fault memory and the engine diagnosis indicator lamp or for CHECK ENGINE indicator lamp lights up. The stored faults can be read out and erased with the STAR DIAGNOSIS.

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