ME-SFI oxygen sensor heater function - GF07.61-P-3024MIS
ENGINE 272.9 in MODEL 221.0 /1 as of model year 2009/ AEJ 08
ENGINE 273.9 in MODEL 216.3, 221.0 /1 as of model year 2009/ AEJ 08
Function requirements for oxygen sensor heater, general points
- Circuit 87M ON (engine control ON)
- Engine running
Oxygen sensor heater, general points
The oxygen sensor heaters bring the oxygen sensors (O2 sensors) up to operating temperature more rapidly. With controlled heating, they also prevent damage to the oxygen sensor ceramics.
Function sequence for oxygen sensor heater
The oxygen sensor heaters differ according to lambda sensor type. The function sequence is described in the following steps:
- Function sequence for wideband oxygen sensor
- Function sequence for non-linear oxygen sensor
Function sequence for wideband oxygen sensor
The O2 sensor on the left and right upstream of the catalytic converter (G3/3, G3/4) are constantly heated while the engine is running to achieve their function.
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)
Function sequence for non-linear oxygen sensor
The oxygen sensor heaters for the LH and RH O2 sensors downstream of the catalytic converter (G3/5, G3/6) are actuated by the ME-SFI [ME] control unit with a ground signal.
To do this, the ME-SFI [ME] control unit (N3/10) 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).
| Electrical function schematic for oxygen sensor heating ME | Model 216 | PE07.61-P-2766-97CAB | ||
| Component description for ME-SFI [ME] control unit | N3/10 | Engine 273 | GF07.61-P-6000MLS | |