Today I was looking at my AC drain to see if is clogged and I found another O2 sensor (the 4th one). Now I am really confused.
Which one is what?
First one is right next to the radiator and has a red heat protector. Second is under the engine in front, where the exhaust pipe curves and goes horizontally. This has blue heat protector. Third one is further back, next to the CAT (i believe) and has white heat protector. I figured this is the rear sensor and I replaced it when I had the engine light on.
Now I found the forth one somehow opposite from the first one (red).

What is the easiest way to identifiy them? Front left/right, rear, before cat/after cat?

 

hmmm..

Ive only read of 3.. could be wrong though..

Bank 1 and 2 by the manafold and 3 by the cat.

Dont know

Proph

 

Thanks Proph

Is there any other sensor that looks like an O2 sensor?

 

maybe this helps:

http://www.courtesyparts.com/A32_O2-sensors.html

 

california emissons

 

Thanks for the replies.
I saw this diagram before but it doesn't help me because my MAX is a 99 (late) and the O2 sensor configuration from the car doesn't really match it.
The rear O2 connector(s) come to the engine bay (not into the bottom of the car as explained on motorvate website)