ME-SFI oxygen sensor heater function - GF07.61-P-3024G
ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08
Function requirements for oxygen sensor heater for the ME-SFI gasoline injection and ignition system (engine electronic) (ME), general points
- Circuit 87M ON (engine control ON)
- Engine running
ME-SFI oxygen sensor heater, function sequence
The oxygen sensor heaters differ according to lambda sensor type. The function sequence is described in the following steps:
- Wideband oxygen sensor function sequence
- Non-linear oxygen sensor function sequence
Wideband oxygen sensor function sequence
To guarantee the function of the left O 2 sensor upstream of catalytic converter (G3/3) and the right O2 sensor upstream of catalytic converter (G3/4) while the engine is run-in, the sensors are continuously heated.
Temperature control and temperature measurement (by measuring the internal resistance) is performed by special control electronics in the ME-SFI [ME] control unit (N3/10)
Non-linear oxygen sensor function sequence
Using a ground signal, the ME-SFI [ME] control unit actuates and synchronizes the oxygen sensor heater for the left O 2 sensor downstream of catalytic converter (G3/5) and the right O 2 sensor downstream of catalytic converter (G3/6).
To do this, the ME-SFI [ME] control unit reads the signal from the coolant temperature sensor (B11/4).
When the exhaust system is very cold (while condensation is present), the oxygen sensor heaters are switched off to prevent damage (due to thermal shock).
| Component description for ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000G |