Hi all,

I have replaced my cats and O2 sensors and still get these codes. They only seem to come on when driving on backroads and in town but I can drive 300+ miles on the highway and the codes will not appear. Truck runs fine, just super annoying to be looking at the check engine light on my dash all the time.

 

I am getting some random errors also after replacing an upstream one. I think as much as anything it is bc they are new? I would bet yours is a loose or dirty wire connection. Those codes would indicate that the catalyst is not working correctly. given they are new, perhaps clean your connections and see how it goes?

 

Swap them around (to check if its an issue with sensor or connectors unless it says both banks are failing) and clean the connectors with qd cean.
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My o2s were replaced in May new exhaust was done last winter. Upgrade to coolant bypass of the thermostat to an inline following the Extinct setup this summer. Just did the pcv 4x4 mod ran great for a 50 mile test cel light came on a few minutes ago with both codes lit red. Possible vacuum leak? Which i will check. New gas cap was done already this year as well. Purge valve done as well. Will check o2 voltages tomorrow which i will post in the what I did today area.
04 disco 2, 4.6l had the Cali emissions valve cover setup.

 

Did you get actual bosh sensors, or cheap ones?

 

My first thought when seeing your post title was:

1) The wrong O2 sensors (by wrong I mean, off brand)
2) Wiring connector issues (they can get super greasy and disgusting and ... yeah)