O2 sensor heater, function - GF07.61-P-3025M
ENGINE 275.950 in MODEL 215, 220
ENGINE 275.951 in MODEL 230 up to Model Year 8
ENGINE 275.953 in MODEL 216, 221 up to Model Year 8
ENGINE 275.954 in MODEL 230 up to Model Year 8
ENGINE 275.980 in MODEL 215, 220
ENGINE 275.981 in MODEL 230 up to Model Year 8
ENGINE 275.982 in MODEL 216, 221 up to Model Year 8
ENGINE 285.950 in MODEL 240
ENGINE 285.980 in MODEL 240
The purpose of the O 2 sensor heater is to rapidly heat up the O 2 sensors to their operating temperature while preventing damage to the sensor ceramic as a result of controlled heating power.
The O2 sensor heater is pulsed (actuated) by the ME-SFI [ME] control unit via a ground signal. The output of the O 2 sensor heater at operating temperature is about 7 W.
Power supply to the O 2 sensor heater occurs for:
- Model 215, 220 from the right front fuse and relay module
- Model 230 from the passenger-side fuse and relay module
- Model 240 from the driver-side SAM control unit with fuse and relay module
- Model 216, 221 from the front SAM control unit with fuse and relay module
In the cold state, the current is increased approximately by a factor of 4. At coolant temperatures under about 20° C and for high engine speeds the O 2 sensor heater is switched off.
Every O2 sensor heater has its own, short circuit proof, output stage which can be diagnosed in the ME-SFI [ME] control unit. As a protection for the ceramic, the O 2 sensor temperature upstream of TWC is limited to approx. 350° C in the condensation phase after the cold start. After this, the temperature is controlled to approx. 700° C. To do this an exhaust temperature is determined from various engine operating data and appropriate heating takes via the O2 sensor heater.
Different values apply to the O 2 sensor heaters downstream of TWC.
| ME-SFI [ME] control unit, location/task/ design/function | GF07.61-P-5000M |
| O2 sensors, location/task/design/function | GF07.04-P-4103M |
| Crankshaft position sensor, location/task/ design/function | GF07.04-P-4116M |
| Coolant temperature sensor, location/task/ design/function | GF07.04-P-5026M |