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O2 sensor heater, function - GF07.61-P-3025KE

ENGINE 271.921 in MODEL 203 

ENGINE 271.940 in MODEL 203, 209 

ENGINE 271.941 in MODEL 211 

ENGINE 271.944 in MODEL 171 

ENGINE 271.946 in MODEL 203 

ENGINE 271.948 in MODEL 203 

ENGINE 271.955 in MODEL 209 

ENGINE 271.956 in MODEL 211 

Fig 1: O2 Sensor Heater, Function (Engine 271)
G04738379

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 as a result of controlled heating.

2  sensor upstream of TWC (broadband oxygen sensor) 

The O2 is heated constantly when the engine is operated in order to guarantee sensor functions.

The temperature control and temperature measurement (by measuring the internal resistance) is performed by the ME control unit using special control electronics.

2  sensor downstream TWC 

The O2 sensor heater is actuated and pulsed by the ME 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 as a protection for the sensor ceramic.

Voltage supply to the O2 sensor heater takes place over the ME control unit from the front SAM control unit with fuse and relay module/driver.

  Component description for the crankshaft position sensor L5 GF07.04-P-6010KE
  Component description for the coolant temperature sensor B11/4 GF07.04-P-6040KE
  Component description for an O2 sensor G3/1, G3/2 GF07.04-P-6100KE
  Component description for the ME control unit N3/10 GF07.61-P-6000KE