How do you replace o2 sensor 1997 BMW 740i?

Answer 1

I have a 99 740 and there are four o-2 sensors. Two located in the exhaust behind the cat converter which are easy to locate. The other two are located in the exhaust in front of the cat conv and up in a not too easy place to reach or even see unless you raise the vehicle high enough to get underneath and look at the area where the exhaust rises up toward the engine. You can see the sensors screwed into the exhaust and follow the wires to their junction boxes located nearby. No problem once car is up in the air.