2001 XJ- How many 0xygen Sensors?

I have a 2001 XJ I just bought as a project truck (it had been wrecked). I have a check engine light that gives the P0158 code.

Here's what the Auto Zone description is:

So, question: When I crawled under to see if I had a cut or shorted wire on O2 sensor #2, I couldn't find one anywhere near the cat or down stream of it. The only sensor I can find is in the exhaust manifold (sensor #1)

Does the 2001 have 2 sensors? Should there be one at my cat? There is no loose wiring, or a bung for one to be mounted in the area that I could see. I had a 2000 XJ a few years ago that I had to pull the cat on, but I can't remember if it had an o2 sensor there or not.

The cat looks to be stock (the flanges are there, and don't look modified like if he had a new one welded in)....

Is there a #2 o2 sensor in 2001? Or, is the Autozone telling me incorrect information (I also don't see how bank2 can apply to an in-line engine either?)


Is there anything else that could be the cause of the code? I saw a post about a TSB on fuses blowing and throwing the code, but I checked and mine are not blown.

Thanks

I believe there are four - two in the exhaust manifolds (I think it's split into two banks of three) before the catalytic converters, and two after the "pre-cats" bolted to the exhaust collectors. I may be wrong - but it should be easy to check.

OBD-II can be picky, and I've not had much faith in "universal" sensors anyhow.

Anyhow, "Bank #1" is probably cylinders 1, 2, & 3; and "Bank #2" is 4, 5, & 6.

5-90

There are 4 O2 sensors actually. I have a 2000 and I had to have the NAPA guy follow the recomendations for a 2001. Anyway, there are no sensors around what I thought was/is the actual cat. The exhaust manifold is grouped into two banks of three tubes. Those banks end in a collection chamber. There is an O2 sensor before each collection chamber and after. I pulled all of them and took them to the part store to make sure I got the right ones back. hopefully this helps...

Interesting..... I'll have to look closer.

I was crawling under the car in the Autozone parking lot in the rain, so maybe I missed it? While I was under there, I did find 4 wires, on the driver's between the tansmission and drive shaft, coming out of a harness (round plug) going to nothing that looked like the front drive shaft mat have caught and ripped out of somewhere.

I haven't tried to track down where they are supposed to go to, but does the XJ have 1 wire or 4 wire o2 sensors? I wonder if these wires could go to a hidden o2 sensor I didn't see?

Thanks for the info.

3-wire or 4-wire. The AMC242 has always used a "heated" oxygen sensor (thus, "HEGO") which has a minimum of three wires.

Typically, a 3-wire will have two wires for the heater, one for the sense, and is self-grounding. A 4-wire should have two separate circuits, "source" and ground for the heater, and "sense" and ground for the output.

5-90

It depends on where the vehicle was built for.My 2000 does not have the pre-cats and only has 2 O2 sensors,1 at the downpipe collector and 1 at the cat!

RCP Phx said:

It depends on where the vehicle was built for.My 2000 does not have the pre-cats and only has 2 O2 sensors,1 at the downpipe collector and 1 at the cat!

Click to expand...

diddo, my 99 has the same, not 4

my 2000 has two. one on the manifold, and one after the cat. It depends whether or not you have federal or state emissions.