I bought a 2007 Jeep Wrangler with 109k miles on Dec 31, 2019 from a small dealer. On Jan 1, 2020 the check engine light came on. The code is P0420 and P0430. I took it to a reputable Jeep mechanic and he said the catalytic converters had recently been replaced. He recommended I replace the O2 sensors with new factory ones, which I did. He said everything checks out fine and he is stumped. If I clear the check engine light it stays off until I get gas. When I get gas it comes back on. Any thoughts?
2007 Jeep Wrangler with P0420 and P0430 codes
- Thread starter Bgjeep
- Start date
Chris-yeah we used the factory O2 sensors. So I don’t think that is what is triggering the check engine sensor.
The next thing I would guess then (and this is actually fairly common) is a short in the wiring somewhere. The problem is of course finding the short, as you typically have to spend a lot of time inspecting the entire wiring harness very, very thoroughly.
However, I'm almost betting you may end up finding a short in the wiring harness where it is grounding out on the body. This is a notorious issue on FCA vehicles, as they do a pretty crappy job of routing the wiring harness sometimes. It will end up rubbing against the body and wearing through the wiring in random places.
People end up throwing tons of parts and money at it trying to fix the issue, only to realize after so much frustration that it was a short in the wiring.
If the Cats are high flow then that will explain why those codes are there. I put long tube headers and high flow cats on my JKU and the same thing happened. I put these O2 foolers on and reset my Codes and they never came on again. https://www.amazon.com/gp/product/B07TT27HPV/?tag=jkforum-20
Also you only put those Foolers after the Cats.
Also you only put those Foolers after the Cats.
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Twisted289
Member
My thoughts exactly. I had that happen to a friend of mine on Ram truck. Aftermarket Cats were throwing the CEL all the time.
Twisted289
Member
He had the mechanic change out to factory cats, cost him a lot more but no codes afterwards. The mechanic did warn him that aftermarket cats could cause that very issue.