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

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 

The ME-SFI [ME] control unit (N3/10) determines the lambda mean value from the oxygen sensor signals downstream of TWC. This value is compared with a stored value for optimum exhaust emissions.

If the deviation is too large after taking a number of measurements, a correction value for the lambda regulation is determined.

The correction variable (value for new oxygen sensor upstream of TWC approx. 0) makes it possible to compensate for aging of the oxygen sensors upstream of TWC within certain limits. If the correction value exceeds the prescribed limit value, the oxygen sensor upstream of TWC [KAT] must be replaced.

The correction value is dependent on the performance map and is achieved by the ME-SFI [ME] control unit by adapting the injection time.

If the prescribed limit value is exceeded or the result of the plausibility check of the oxygen sensor signals (upstream or downstream of TWC) is negative, the engine diagnosis indicator lamp (A1e58) lights up in the instrument cluster (A1).

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

Two sensor control is only enabled when the catalytic convertors have reached their operating temperature and the oxygen sensors downstream TWC are correct.

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

REFER TO SYSTEM WIRING DIAGRAMS Electrical function diagram for two-sensor control   PE07.61-P-2763-99FAB
  Component description for fuel injection valves Y62/1-Y62/6 GF07.03-P-6010CY 
  Component description for the oxygen sensor G3/3, G3/4 Oxygen sensor upstream of TWC [KAT] GF07.04-P-6101CY 
G3/5, G3/6 Oxygen sensor downstream of TWC [KAT] GF07.04-P-6101CZ 
  Component description for the ME-SFI [ME] control unit N3/10 GF07.61-P-6000CY
  Component description for the three-way catalytic converter 157 GF49.10-P-2010CY
  Component description for the engine diagnosis indicator lamp A1e58 GF54.30-P-5010CY