I just got a 99 XJ. The 02 sensor behind the cat had the wires ripped out when I got it. I bought a new one replaced it, zip tied it away from the drive shaft. After I replaced it with new one it was running strange. Then I decided to check the fuse under the hood, sure as **** it was blown. Replaced the fuse, check engine light went off. Drove it for a day and check engine light came back on. Put a scanner on it and the coad read hi voltage on the rear 02 sensor and also said mechanical malfunction in the torch converter. So I checked the fuse again to make sure I wasn't having a bad wire issue and the fuse was good. It no longer runs strange and the tranny is shifting fine, everything seems fine. Anyone have any info on this topic??

 

The rear o2 sensor has no bearing on how the motor runs.

It's just there to tell you the cat isn't working. It does absolutely nothing else.


Except trip CELs when the wires get ripped off.