ENGINE   275.950 /980 in MODEL 215

Illustrated model 215, 220, 230, 240 B11/4 Coolant temperature sensor G3/3 Left O2 sensor upstream TWC G3/4 Right O2 sensor upstream TWC G3/5 Left O2 sensor downstream TWC G3/6 Right O2 sensor downstream TWC K40/4 Passenger-side fuse and relay module (model 230) K40/7 Passenger-side right front fuse and relay module (Model 215, 220) L5 Crankshaft position sensor N3/10 ME-SFI control unit N10/1 Driver-side SAM control unit with fuse and relay module (model 240)
		P07.61-2920-05

The purpose of the O2 sensor heater is to rapidly heat up the O2 sensors to their operating temperature while preventing damage to the ceramic material as a result of controlled heating power. The sensor heater is actuated by the engine control unit through pulsed ground The power output of the sensor heater at operating temperature is approx. 7 watt. The voltage for the sensor heater is supplied by the: Front right fuse and relay module, model 215, 220 Passenger-side fuse and relay module, model 230 Driver-side SAM control unit with fuse and relay module, Model 240.

In the cold state, the current is increased approximately by a factor of 4. At coolant temperatures below approx. 20 °C and at high engine speeds the sensor heater is switched off. Each sensor heater has its own, short-circuit proof output stage in the engine control unit with diagnosis. As a protection for the ceramic, the sensor temperature upstream of TWC is limited to approx. 350 °C in the condensation phase after a cold start. The temperature is subsequently controlled to approx. 700 °C. For this purpose, the exhaust temperature is determined using various engine operating data and the sensor heated accordingly. Different values apply to the O2 sensor heaters downstream TWC.

	ME-SFI 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