Hi. I recently bought a 2000 Cherokee sport and my check engine light came on a week later. I took it to autozone and they did the check engine light test and said it was my o2 sensor bank 2. I was underneath looking and I think I have 4. 2 up on the manifold and 2I on the pipes that run down. I replaced the one they told me was bad and it was good for a day now its back on. Has anyone had the same problem or know what to do. I'd appreciate it. Thanks. Brandon

 

Yep, trying to get information on how to diagnose it now. See this POST

Do you remember the code number? There are a few different codes for the same sensor. Mine is P0156. Be sure to post any progress you make and I will do the same.

 

You guys might want to look at MrTowers 02 thread as well. He is sorting out what seems to be a similar problem.

 

Did you erase the code after the part was replaced?