0330qa4

Where are the O2 sensors plugs on the 3.0? Specifically bank one side. I know the bright green plug is one but there arent anymore 4 pin plugs near it. I just want to know if its black 6 pin one to the left of it. Need to replace one.

Millatime

under the coolant resovior?

0330qa4

For reference
If you are in front of the car looking at the engine bay there are two plugs on the left and two on the right.

On the left (Bank 1)
There is a green plug with four pins
Two plugs to the left of that is a black plug with 6 pins

On the right (Bank 2)
You have to unscrew the coolant reservoir
There is brown plug with four pins
Two plugs to the right it is a black plug with six pins

The black plugs are pre cat (Sensor 1)
the colored plugs are post cat (Sensor 2)

A6SilverBack

I know this sounds like a stupid question, but I can't see or reach the front O2 sensors. How do you get to them to replace them?

The Bentley manual is worthless for this job. The BMW Bentley manual walks you through the whole job step by step.

Millatime

not sure how different the 3.0 is but after you get the resovior off you should be able to see the exhaust pipe as it runs back toward the firewall. the passengers side one you can see if you take apart the intake ducting from the airbox to the throttle body.

it was a pain to get at either of them from the top because of the angle they face relative to the firewall.

i had a crows foot style O2 Sensor socket and about 18" of extentions so i could clear everything. i started the car up and let it run for a minute or two to heat up the pipe to make it easier to break free. took some fussing with and some burns on my knuckes but once you break em free from underneath you should be able to reach in from the top.

kjcrede

I'm looking for the same thing, and came across your original post..
Did you ever get a good answer for the location of the pre-cat 02's