O2 sensor


Cost: $80


Buy it now


The Bmw Oxygen sensor measures the amount of oxygen in the exhaust after combustion and signals the computer to adjust the air/fuel mixture.

Poor performance, poor fuel economy and high emissions are the failure syndromes.

Check this great O2 sensor FAQ.


  • 02 sensor socket (can be purchased at Autozone)
  • Lot's of WD 40
  • Rachet, extensions and u-joints
  • Anti seize compound

Place the front of the car on jacks or use a ramp, then spray the old sensor with a lot of WD40 (with cold exhaust). Let it sit for awhile then you can remove the sensor with the sensor socket some extensions and u-joints. Don't forget to apply a coat of anti-seize compound on the new sensor threads. NOT on the tip!!!

In any model, you don't have to remove any part of the exhaust line.



M20 : The O2 sensor is located below the #6 cylinder on the front of the exhaust pipe. The connector is located on the right-hand rear of the engine, near the electronics box.

M50 : The O2 sensor is located at the front of the catalytic converter. The connector is located on the left-hand side of the engine, below the starter.


530i - 540i

The M60 engine uses two O2 sensors located at the front of the catalytic converters.

The connector is located beneath the car under the transmission.



The 535i uses a single O2 sensor located at the front of the catalytic converter under the car. The connector is located at the rear of the engine compartment, lower left-hand side.


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