Devlin Clark

I have replaced the 02 sensor bank1 sensor 2 with one from NTK and now one from the jeep dealer and both times after about 20 minutes drive time the code ( P0139) comes back.

karls10jk

So you've got to look further into the diagnosis. I don't have the manual in front of me but usually these codes call to make sure you're getting voltage to the pigtail and that one wire is a ground. You've purchased the correct brands of parts, did they sell you the sensor for the correct position??

Devlin Clark

The Auto Zone sold me the wrong sensor that is why I went to the dealer, oneof the techs said it sounded like it was in the wire harness and when I asked how much it would be to replace he said over $500 for them to do it. I'm retired and alittle disabled so I cant do it myself. I can however buy a multimeter and a manual

Mr.T

Just a double check: Bank 1 is passenger side and sensor 2 is after the cat. That's the sensor you replaced, correct?

Devlin Clark

Correct I also checked for a exhaust leak, none found.
The 02 wire harness after sensor 2 plug has outer insulation (part covering all wires) open but actual covering over individual wires looks ok.

Mr.T

Here's the possible causes, and some details on P0139. I'd connect the laptop (or other scanner) and graph the O2 sensors plus RPM and take a drive. It's way easier to troubleshoot when one can see exactly how the sensor voltage is acting, especially when it's an engine with two banks for comparison.

Incidentally, if anyone has installed spark plug anti-foulers in the threaded hole for the O2 sensor to try and fix a cat efficiency DTC -- That would probably be the problem.