How many 02 sensor are there in a 99 bmw 323ic

SOURCE: How do u change 02 sensor on a bmw 545i and how

Hello 282,

There are a total of 4 02 sensors on your vehicle. Each side of the engine has 2 02 sensors. 1 sensor is located before the catalytic converter, and 1 sensor after the converter for each exhaust. You will have to remove the lower plastic covers under the car to access where the sensors are located. They are located in the exhaust forward of the transmission. You will need either a 22mm or 24mm open end wrench, or preferably an oxygen sensor removal tool which can be purchased from an automotive store or even Sears. In addition you may need a 3/8 ratchet.The sensors can be pricey and I recommend staying with Bosch brand if possible. It is best to remove the sensors when the exhaust is cold.