Rear Oxygen Sensor

Rear Oxygen Sensor, B235E/R

To Remove

Important: The cables must not be twisted. The oxygen sensor is very sensitive to impact and jolting and must be handled with care.






1. Remove the upper engine cover.
2. Remove the oxygen sensor connector from the holder by pressing the lugs together as shown in the illustration.






3. Uncut the cable tie to the oxygen sensor and draw out the cables.
4. Raise the car.
5. Pull down the cable and remove the oxygen sensor.

To Fit

Important: The oxygen sensor is sensitive to impact and jolting and must be handled with care. It is important that the connections between the oxygen sensor and nipple are gas-tight.

1. Coat the oxygen sensor threads with Molycote 1000 (30 20 971) to prevent binding.






2. Fit the oxygen sensor.
Tightening torque 55 Nm (41 ft. lbs.)
3. Lead the cable as far up as it will go. Lower the car.

Important: Watch out for sharp edges, warm components etc.






4. Draw out the cable and plug in the connector.

Important: Chemicals such as contact spray and grease must not come into contact with the oxygen sensor connectors.

5. Fasten the cable to the water pipe with a cable tie.
6. Fit the upper engine cover.