My wife's 2004 TJ (4.0/Auto) threw a MIL a couple months back. Showed P0138 and P0158, which is high voltage on downstream O2 for both banks. Replaced both sensors hoping it was an easy fix, but after about 30 miles of driving the light came back on, throwing the same codes again.
I've traced all the wiring I can find from the O2 sensors but the entire harness, the grounds, etc all look brand new (part of why I bought the Jeep).
I'm at a loss and could use the advice of those in the know. Anyone have this problem before and come up with a proper resolution to this problem?
Mine: 2012 JKU Sport, Deep Cherry, Auto, 3.73s, Rock Krawler 3.5" Flex, chitty Procomp shocks, JKS Discos, Rubi rails, A.C.E. sliders, EVO ProTek Skids, EVO Rockstars, JCR Dagger with lights and tire carrier, PSC Brawler Lite with custom stinger and grill hoop, ENGO 10k with synthetic, 35x12.50-15 BFG KM2s, MOPAR flat flares.
Wife's: 2004 TJ Sport, 4.0/Auto, 2" BB, stock JKU shocks, JKS front LCAs, 31x10.50-15 BFG ATs.
Did you ever figure this out? I have the same exact codes being thrown on my 2004 4.0. I had P0432 about a month ago and installed dummy o2 sensors I bought online. The P0432 code went away and now I'm getting p0138 and p0158.
Not sure if he got his problem fixed but a common problem with o2 sensors in the TJ is that they were replaced with sensors other than NTK brand. Rock auto has them for the cheapest that I have found. Only the NTK brand will perform properly for an extended period of time for us.
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