Replacing Both Oxygen Monitor Sensors

Read out fault memory, clear if necessary.





E46 only
Remove microfilter.
Open cable duct on lower section of microfilter housing (2) and feed out cable(s).
Release screws (1) and remove lower section of microfilter housing (2).





Remove cover from injection valves.

Note: Do not mix up oxygen monitor sensors for cylinders 1 to 3 and 4 to 6 at plug connection to wiring harness.

Mark plug connections.
Unclip the cable from the retainer. Disconnect plug. Unclip cable on rear side of engine from cable guide.





Release oxygen monitor sensor from cylinders 1 to 3 with special tool 11 7 030.
Release oxygen monitor sensor from cylinders 4 to 6 with special tool 11 7 020.

Installation:
The threads of new oxygen monitor sensors are already coated with Never Seez Compound.
If an oxygen monitor sensor is used again, apply a thin and even coat of Never Seez Compound to the thread only.
Part of oxygen control sensor that projects into exhaust system branch must not be cleaned or come into contact with lubricant.





Installation:
Secure oxygen monitor sensor for cylinders 1 to 3 with special tool 11 7 030.
Secure oxygen monitor sensor for cylinders 4 to 6 with special tool 11 7 020.
Tightening torque, refer to Specifications, Mechanical.
Cover oxygen monitor sensors when applying underseal.
Pay attention to cable routing of oxygen monitor sensors.