Removal and installation the oxygen sensor (BMW 3 Series E46)

The BMW 3 Series has oxygen sensors located before and after the catalytic converter to ensure exhaust gas purity is monitored.

Connecting cables of oxygen sensors are not repaired or soldered. If there is damage, the cable is replaced as a set.

Removal

The operation of lifting and installing the vehicle on stands is associated with danger! Therefore, before carrying out the operation, read the Section Jacking and towing

1. Raise and support the vehicle on stands.

2. Models 316i, 318i: Disconnect connector "3" of the oxygen sensor and unscrew sensor "4" from the inlet pipe.



3. Models 320i, 323i, 328i: Disconnect the oxygen sensor plug connections (two arrows on the right in the illustration).

Mark the plugs to avoid confusion during assembly. Remove the engine cover to expose the plugs, refer to Section Removal and installation the lower engine compartment cover.

4. Disconnect the cable holder (left arrow). Unscrew the oxygen sensors from the inlet pipe. To do this, you will need a socket wrench, for example, HAZET 468/4.

Installation

Do not clean the oxygen sensor in the apex area or allow it to come into contact with grease. Cover the sensors when applying a protective coating to the bottom.

5. Coat the oxygen sensor threads with special high-temperature grease "Nevar seez Compound".

If the oxygen sensor is screwed in without high-temperature grease, the threads will burn over time and the sensor will be impossible to unscrew. New sensors have a corresponding coating.

6. Screw the oxygen sensor into the inlet pipe and tighten to 55 N·m.

7. Route the electrical wire so that it does not fray or come into contact with the exhaust system.

8. Install the engine cover.