P0161 (4 new sensors) but no exhaust past 3 catalytic converters

[jcw]

Hey, I have been chasing some CEL exhaust codes for a while. I had to replace the cats due to internal damage. Got a new front double pre cat from Eastern/Davico that bolted up good and I replaced the third cat with the same brand but for an XJ model as that one bolted straight up to the first two cats with no welding.

Jeep was produced in FL so shouldn't have any crazy restrictive emissions controls. All 4 o2 sensors were replaced with NGK which fixed my previous CEL code but since I haven't been able to get rid of this P0161 code

I don't have anything on past the third cat (no muffler or tailpipe) and it sounds amazing but Im wondering if that is causing the P0161 code that I can't seem to get rid of.
Gas mileage seems to suck as well

 

[RMETeeJay]

If that code returns quickly after clearing codes, it's likely that the wiring is the issue on your bank 2 (post catalyst) sensor. Inspect and make sure nothing is touching the exhaust and melting, etc. When I last replaced my sensors, I had to use a lot of force to fully close the connector and hear the click.

It might also be worth trying the XJ specific sensor for bank 2.

 

[AndyG]

That wire lays on the back of the block practically if I remember correctly- really look close. @John Cooper impressively found a short recently by feel only- was non visible.

All the best, good post above as well RME.