Downstream O2 Sensor Help!

All,

I cannot pass the DEQ emissions test because I cannot seem to keep my O2 sensor working for more than 1 day. I have replaced my O2 sensor, twice now and get the same results. I get a P0138 code. I have a 2000 Jeep Cherokee Classic 4WD, XJ.

Initially, after replacing the sensor, everything is running fine, I get a reading of 0.4-0.42 V from the Bank 1 Sensor 2, then all of the sudden it will start reading 1V and then throws the code. It seems like then sensor works for a couple of hours of running then just gets cooked! The last one I used was a Bosch sensor. I don't know what else, the wiring seems fine and I would assume is good because I get a decent reading for a while before it fails.

Here's the sensor I just installed and it appears to have worked for only 1-2 days.

Bosch 13138 Oxygen Sensor, OE Fitment (Chrysler, Dodge, Jeep)

Is it possible my PCM is just bad? Could it be my catalytic converter?

 

Quite a few things can trip that code besides the PCM:
https://repairpal.com/obd-ii-code-p0138

Also NGK sensors are what the factory uses. NOT saying the Bosch is the problem though.

 

That sensor's only job is to monitor the health of the cat converter. Try a bottle of Cat a Clean and clear the code, if it takes a while to come back suspect time for a new cat. Suspect a new cat anyway.

 

Any recommendations on the best Catalytic Converter to use? Will a cheap one work?

 

If it's the original cat that hasn't been upgraded you may be able to get a free replacement:
https://www.epa.gov/enforcement/daim...ion-settlement

 

What voltage should I be reading on the vehicle connector to ensure the wiring is OK?
What voltage should I be reading on the vehicle connector to ensure the wiring is OK?

 

Yes, just replace the Cat, cost me $100 for a 2-1/2" unit and $50 to get it welded in. ( and thats Australian dollars/pesos)

Check Rock Auto

My cheap aftermarket O2 sensor also failed shortly after, I fitted a used OEM sensor, all good