I have a 2001 Cherokee Limited 4.0L XJ with CALIFORNIA emissions system.

It has been throwing P0155.

Correct me if I'm wrong but to me that means I need to replace the BANK 2 SENSOR 1 (REAR UPSTREAM SENSOR). Is that correct? If so, the information I have found thus far directs me to replace it with NTK 23506. Is that correct as well?

I have been scouring forums all day long to find an answer to these questions and have gotten conflicting information. If you have any input please reply!

Secondly, this 2/1 o2 sensor seems very hard to access to replace. How do I go about doing this?

-Adam

 

Yes that's that right part number for that sensor. I need to replace that one as well on mine. They take a 7/8" wrench or if you can find one of those O2 sensor sockets those work as well. As for getting it off, PB Blaster soaked and a lot of elbow grease. They come out easy sometimes and others they don't. It seems kinda hard to access that one but the best way is from underneath. Preferably while on a vehicle lift. If you don't have access to one then jack stands will suffice but you'll be doing the work on your back.

 

I just replaced all the o2 sensors on our XJ and Blazer. Went to Advance Auto and got their 3pc o2 socket set. You pay for it($30?) and take it back for a full refund when your done. Makes it NICE to have the right tools.