No engine harness wires for O2 sensors

[Lucky7]

So I owned my jeep for about two years before I randomly got a check engine light for P0132 “O2 sensor circuit high voltage bank 1 sensor 1”. I thought I had a bad O2 sensor I looked and the sensors had the wires cut off at the base. I also can’t find the wires that come off the harness that would plug into the sensors. I looked at a friends jeep and he has a whole plastic piece running next to the intake manifold with these harness wires inside it, I don’t have this at all. The engine was swapped at one point also. I’m just not sure why it took two years for the light to come on and if both O2 sensors aren’t plugged in I’m only getting one code for it. I can’t get it inspected or registered because of this code if anyone could help me out that would be appreciated. I added photos of my engine bay and two random harness wires that aren’t plugged into anything.

 

[Jerry Bransford]

Your older TJ has two O2 sensors. For the first one, look under the exhaust header and just below where the exhaust pipe leading to the exhaust system bolts to it. That's where you'll find the upstream O2 sensor, the downstream O2 sensor is screwed into the catalytic converter. Both O2 sensors have four-wire connectors, the one in your photo only has two so it's not the O2 sensor connector.

 

[Mitchrb1]

Not sure if this helps with up top. but, the 02 for front bank I believe is the gray plug on the far right. I have it zip tied above the Crankshaft position sensor plug in.

 

[Gilaguy23]

It took you 2 years to look under your jeep is what your saying? Ever inspect your frame/skid area, C arm mounts for accident causing cancer?

 

[ChestnutHill]

I posted about this exact scenario a couple of weeks back… I think this might help:

https://wranglertjforum.com/threads...ation-2000-o2-sensor-help.70822/#post-1338939

 

[reddvltj]

Your older TJ has two O2 sensors. For the first one, look under the exhaust header and just below where the exhaust pipe leading to the exhaust system bolts to it. That's where you'll find the upstream O2 sensor, the downstream O2 sensor is screwed into the catalytic converter. Both O2 sensors have four-wire connectors, the one in your photo only has two so it's not the O2 sensor connector.

Just an FYI for those that go looking...
The downstream sensor (Bank 1 Sensor 2) on the 2000 Federal Emissions and 1999 my is after the cat not in it, and the Upstream (bank 1 sensor 1) is just in front of the cat and trasnfer case skid plate.

 

[Lucky7]

It took you 2 years to look under your jeep is what your saying? Ever inspect your frame/skid area, C arm mounts for accident causing cancer?

Gonna be honest I always knew they were cut but it didn’t have any check engine lights so I was like hmm guess that’s not a problem right now.

 

[Lucky7]

I posted about this exact scenario a couple of weeks back… I think this might help:

https://wranglertjforum.com/threads...ation-2000-o2-sensor-help.70822/#post-1338939

Mine is also a 2000 and has the newer style dual pre cat o2 sensor headers and they’re both cut off. I’ll have to look into this, it sounds like this is exactly my problem.

 

[reddvltj]

Mine is also a 2000 and has the newer style dual pre cat o2 sensor headers and they’re both cut off. I’ll have to look into this, it sounds like this is exactly my problem.

2000 came in federal emissions/export version and CA emissions version.

Are you absolutely sure yourjeep is the CA emissions and not the Federal emissions? What does the engine sticker under the hood say?

Federal emissions on the 2000 model year uses the same exhaust design and the 1999 model year 4.0l. The CA emissions "y" pipe will bolt right up the Federal emissions manifold and vice versa.

 

[Lucky7]

So my engine was swapped at one point would it make sense if they left the exhaust manifold from the new engine on and just bolted it to the old y pipe in the car. So the only are two real o2 sensors before and after the cat?

 

[reddvltj]

So my engine was swapped at one point would it make sense if they left the exhaust manifold from the new engine on and just bolted it to the old y pipe in the car. So the only are two real o2 sensors before and after the cat?

View attachment 431953

View attachment 431954

That's exactly what it looks like. If you had the CA emissions there would be a pre cat on each tube (red) and and 2 more O2 sensors right after them (yellow). So the 2, O2 sensors you need are for the Federal Emissions 2000 model year, and they will both be down under the Jeep, 1 in front of the skid and the other between the cat and the muffler.

 

[reddvltj]

So my engine was swapped at one point would it make sense if they left the exhaust manifold from the new engine on and just bolted it to the old y pipe in the car. So the only are two real o2 sensors before and after the cat?

View attachment 431953

View attachment 431954

On that note, if you are in a state that does visual inspections during emissions testing, I would see about getting rid of the non functioning O2 sensors and put plugs in their place, or even better get a new set of front and rear manifolds that don't have the bungs.

 

[Andy-WhiteTJ]

BTW, those 2000 Federal Emissions down pipes are no longer available. Take care if you need to remove them and work on them.

 

[reddvltj]

BTW, those 2000 Federal Emissions down pipes are no longer available. Take care if you need to remove them and work on them.

I guess a guy could pony up the $$ for the one with precats nd either cut them out or have a complete custom y pipe made... That sucks!!!

 

[Lucky7]

Now starts the fun part of trying to get 150k mile salty road o2 sensor out to fix the engine light

 

[reddvltj]

Now starts the fun part of trying to get 150k mile salty road o2 sensor out to fix the engine light

Good luck!!! heat and penetrating spray will be your friend!!!

 

[macleanflood]

Now starts the fun part of trying to get 150k mile salty road o2 sensor out to fix the engine light

I'd seriously heat it up with a torch... maybe even cut off the bung and weld on a new one.

Good luck!

-Mac