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

ENGINE 104.941 /943 /944 /991 /994 as of 1.8.96 with CODE (494a) USA version 

ENGINE 104.995 with CODE (494a) USA version 

ENGINE 111.921 /942 as of 1.9.98, 111.943, 111.944 as of 1.8.96, 111.946 as of 1.6.98, 111.947 /973, 111.975 as of 1.8.96 with CODE (494a) USA version 

ENGINE 111.945 in MODEL 202.020 /080 as of 1.9.98, 208.335 /435 as of 1.6.98 with CODE (494a) USA version 

ENGINE 111.951 /952 /955 /956 /957 /958 /982 /983 

ENGINE 111.974, 112.970 /972 with CODE (494a) USA version 

ENGINE 112.910 /911 /912 /913 /914 /916 /917 /920 /921 /922 /923 /940 /941 /942 /943 /944 /946 /947 /949 /953 /954 /955 /973 /975 with CODE (925) low emission EURO3 with CODE (926) low emission EURO4 with CODE (494a) USA version 

ENGINE 113.940 /941 /942 /943 /948 /960 /961 /963 /965 /966 /967 /968 /969 with CODE (925) low emission EURO3 with CODE (926) low emission EURO4 with CODE (494a) USA version 

ENGINE 119.980/981 /982 /985 with CODE (494a) USA version 

ENGINE 120.982 /983 with CODE (494a) USA version 

ENGINE 137.970 

Task 

The engine control unit calculates the lambda mean value from the signals supplied by the oxygen sensor downstream of TWC. This value is compared with a stored value for optimum exhaust emissions. If the variation of several measurements is too large, a correction variable (lag time ± TV) is determined for the lambda control.

Use of the correction factor (value for a new O2 probe about 0) allows one to compensate for aging of the O2 probe upstream of the catalytic converter within certain limits. If the correction variable exceeds the limit value, the oxygen sensor upstream of the TWC must be replaced.

In addition, allowance is made for the period of the signal supplied by the sensor upstream of TWC. If no sensor state change takes place, the lambda control is not active and no two-sensor control is therefore possible either.

IMPORTANT The effect of the three-way catalytic converter is monitored with the oxygen sensor signals downstream of TWC.

  Motor electronics control unit, location/task/design/function other than engine 111 EVO GF07.61-P-5000F 
    Engine 111 EVO GF07.61-P-5000GS 
  O2 sensors, location/task/design/function   GF07.04-P-4103F 
  Three-way catalytic converter location/task/design/function   GF49.10-P-3002F