PO133 Oxygen Sensor Issue

[PlexusTJ]

Hi Guys,

Hoping for some help, I have an 00’ TJ (RHD is Aus) and the other day I got a check engine light come on for the first time.

On checking the code it says ‘P0133 heated oxygen sensor (HO2S) 1, bank 1 - slow response’. When I got home I took a look in my user manual and decided to take a look at the sensors themselves.

Where it’s become a little weird is that I seem to be only able to find 1 sensor, at the back of the cat, under the plate:

But the service manual says I should have at least 2.

If I follow the exhaust up to where it joins the manifold, there doesn’t seem to be anything but a few plugs:

Does anyone have any idea why it would be missing? Or if it should be? Is this an AUS thing?

Any help would be appreciated.

 

[macleanflood]

I'd look at live ODB data and see which PIDs are available and sending voltage.

Typically a working O2 puts out less than.9v and a gross simplification is if it's going over that voltage it's bad.

You might want to check your cat with an IR gun.

Has your fuel mileage dropped...how do you refer to KMs per liter rather than MPG?

-Mac

 

[GregBelleville]

You should have another O2 sensor on the down pipe right after where it connects to the headers.

 

[PlexusTJ]

I'd look at live ODB data and see which PIDs are available and sending voltage.

Typically a working O2 puts out less than.9v and a gross simplification is if it's going over that voltage it's bad.

You might want to check your cat with an IR gun.

Has your fuel mileage dropped...how do you refer to KMs per liter rather than MPG?

-Mac

Hey @macleanflood

So I turned on the OBDC Bluetooth connector I already have and took a screenshot of the oxygen sensors, no idea if this is good or not?

Still confuses me as it shows 2 sensors but I still cannot find the second one

 

[macleanflood]

So yeah you have two... that's a good confirmation.

You'll want to rev up the engine and get it warm and watch those two voltage numbers to see if they go over .9v.

Lots of crazy stuff done to these Jeeps over 20 plus years by previous owners. Especially ones desperately trying to pass inspections.

On my 97 I have one at the base of my exhaust header just above the crossover pipe flange. And then my second at the back on the skid plate just past my cat.

-Mac

 

[glowell222]

This is a really helpful article:

https://troubleshootmyvehicle.com/jeep/4000/how-to-test-the-oxygen-sensor