O2 sensor heater, function - GF07.61-P-3025AMG
ENGINE 156.980 in MODEL 164, 251
ENGINE 156.982 in MODEL 209
ENGINE 156.983 in MODEL 211, 219
ENGINE 156.984 in MODEL 216, 221
The purpose of the O2 sensor heater is to rapidly heat up the O2 sensors to their operating temperature while preventing damage to the sensor ceramic through controlled heating. O2 sensors upstream of TWC (broadband oxygen sensors) The O2 sensor is heated continuously during engine operation, to guarantee its function.
The temperature control and temperature measurement (by measuring the internal resistance) is performed by special control electronics in the ME-SFI [ME] control unit.
O 2 sensors downstream of catalytic converter (voltage jump oxygen sensors)
The O2 sensor heater is actuated and pulsed by the ME-SFI [ME] 2 control unit via a ground signal. The mean pulsed heating current is approx. 400 mA in idle speed range. The current in the cold state is increased approximately by the factor 4.
The sensor heater is switched off at coolant temperatures below approx. 20°C and at high engine speeds to protect the sensor ceramics.
Voltage supply
Power supply to the O2 sensor heaters takes place via "terminal 87 M".
Each sensor heater has its own short-circuit proof output stage with diagnosis switching to ground in the ME-SFI [ME] control unit.
| Component description for O2 sensors | G3/3, G3/4 | O2 sensors upstream of TWC | GF07.04-P-6100AMG | |
| G3/5, G3/6 | O2 sensors downstream of TWC | GF07.04-P-6100AMH | ||
| Component description for the coolant temperature sensor | B11/4 | GF07.04-P-6040AMG | ||
| Component description for the crankshaft Hall sensor | B70 | GF07.04-P-6220AMG | ||
| Component description for the ME-SFI [ME] control unit | N3/10 | GF07.61-P-6000AMG | ||
| Component description for the three-way catalytic converter | 157, 158 | GF49.10-P-2010AMG | ||