1997 Jeep Wrangler 2.5L

[darkfire5000@yahoo.com]

I have an engine code P0138 it deals with 02 Sensor Bank 1 Sensor 2 I just need to know which 02 Sensor that is so I can test it to see if it is good? Any knowledge of which one it is or a pic would help out a lot.

 

[backinblackyj]

you should have 2 o2 sensors. upstream and downstream.

upstream is before the cat. downstream is after the cat.

if an o2 sensor goes bad i would say 90% of the time it would be the upstream. the downstream doesnt do a whole lot.

someone correct me if im wrong. thats how i understand it...

 

[xt master]

I ran my Jeep for 2 weeks with out the down stream.I actually got better gas mileage?

Upstream O2 sensor is right below where the down tube connects to the manifold.

Down stream is after the CAT right near the back side of the skid plate.

Both are fairly easy to get to from under the jeep.

If I remember correctly it was a 20 or 21mm wrench.

Auto zone sells them for about $54 each.

 

[captjanes]

sensor 2 is the downstream one which is the one farthest away from the engine, after your cat. should be around your transfer case i would imagine. and USUALLY if one is gone then the other sensor aint far behind. hope this helps