Which o2 sensor connector goes to which bank?

[vteckiller2000]

My car has had no front o2's on it for about a week (don't ask), and the shop told me the wiring looms were different colors to identify which banks they belonged to.

They don't.

The looms to both front and rear pre-cat o2's are both black, so I have no idea which sensor to connect to which connector.

Can anyone help me? :crying

[kayger12]

I'll check the Bentley for you when I get home and see if there's anything in there. Be around 6p eastern.

[mikeyb74]

I just had a customer asking me this. The Bentley states in a caution box. "Label connectors so that front and rear connectors are not mixed up" :(

[mikeyb74]

Here is a picture of a post cat o2 sensor

http://www.bavauto.com/assets/imglib500/15681.jpg

Pre cat 02 sensor.

http://www.bavauto.com/assets/imglib500/17215.jpg

The plugs are different. Do you have the old O2 sensors? If you do I could look up the part numbers for them to see which one they are.

[spencers]

Typically the ones with the longer wires are the post-cat, no?

[danewilson77]

I have brand new precats at home. Would pics of those help?

Droid! Srs Legitness!

[vteckiller2000]

No I need to distinguish between the "front bank" and "rear bank" PRE-CAT o2 sensors. The old ones were cut off by the PO to lengthen them, and were gone when I got the car. The wiring looms are both the same color between the front bank and rear bank FRONT o2 connectors, so I can't go by color.

[vteckiller2000]

Anyone who could take their engine covers off and tell me which connector goes to gray and which one goes to black wiring would earn an e-beer from me!

[danewilson77]

Taking my cover off now....

[danewilson77]

Black one forward.....gray one aft....on the passenger side.....

http://i1015.photobucket.com/albums/af278/nicee46/Maintenance%20and%20Misc/IMG_20110404_201620.jpg

http://i1015.photobucket.com/albums/af278/nicee46/Maintenance%20and%20Misc/IMG_20110404_201632.jpg

Service with a smile my friend.

[spencers]

No I need to distinguish between the "front bank" and "rear bank" PRE-CAT o2 sensors. The old ones were cut off by the PO to lengthen them, and were gone when I got the car. The wiring looms are both the same color between the front bank and rear bank FRONT o2 connectors, so I can't go by color.
The pre-cat o2 sensors are the exact same model o2 sensors; for "front bank" and "rear bank."

[danewilson77]

Ok...so they wouldn't be diff colors necessarily....correct?

Droid! Srs Legitness!

[spencers]

Ok...so they wouldn't be diff colors necessarily....correct?
If they're the same exact brand and model, no.
Look at realOEM. It calls for 2x of the same o2 sensor.

[vteckiller2000]

Both pre cat sensors are essentially the same, though they are different in OEM and bosch number. Thanks bud, but I need the other end. I know which sensors go to which bank, but I need to know which sensor leads go to which connector. Under the driver's side engine cover...

[danewilson77]

Define "under engine cover". I stopped making dinner to go do that..lol. Thought I knew what you wanted.

[spencers]

Ohhhhh, the CONNECTORS??

I wish I knew about the wiring. See if you can get Dane to snap a photo.

Dane, I think he means the plugs where the o2 sensors connect. They're right above the o2 sensors; held by metal clips.

[danewilson77]

I still don't understand. I removed the engine covers, and snapped the O2 sensors. I have not had to replace....so, I am prolly being dumb.

[spencers]

I still don't understand. I removed the engine covers, and snapped the O2 sensors. I have not had to replace....so, I am prolly being dumb.
lol
Not the sensors themselves... I think he wants to see where the sensors plug in to, electronically. I'm still confused, too. :rofl
FYI: no engine covers have to be removed to access pre-cat sensors or connectors.
http://www.availabledark.com/images/bmw/o2diy11.jpg

[danewilson77]

You gotta be shitting me :shifty.

[vteckiller2000]

On the post 2003 model year 330/ZHP, they used wideband sensors on the front o2's. The connectors for those are no longer on the far side of the engine, but under the engine cover which covers the fuel rail, the one that doesn't cover the coils and oil cap. It has a six pin connector, with five wires in it for each front o2 sensor. They are not the round, 4 pin connectors pictured ^^ above.