I generally do not post, i utilize the search function until I exhaust all possible solutions but this one has me at my wit's end. I keep having this error code come up, I have replaced all four o2 sensors thinking that was the problem, I cleaned my MAF based on a suggestion that I read here. What's next? replace the cats? I can clear the code and it comes back after 30-40 miles. My ultra-gauge shows consistent voltage readings across all o2 sensors so I thought I was good, but then again it showed the same even before I replaced them. thank you in advance guys.

 

Your readings should not be "frozen", they should be changing always, and the fronts change more than the rear. The system believes your rear O2 sensors are detecting a marginal catalyst as to oxygen storage capacity to the federal standards. That black SUV that has been following you is the EPA...

Pages of how system determines this from Bosh manual on the ECU and codes. Sounds "cat-astophic".

 

Faulty O2s don't typically throw that code, generally means it's time for new cats.

 

by consistent I did not mean that they stayed the same, only that the readings didn't look obviously different from sensor to sensor.

 

I missed the fact that you've an '04. Anythings possible but unless you've a ton of miles, it shouldn't be an issue with the cats. Have you had any prolonged issues with running rich or put anything through the system that could have damaged them? Also the issue lies on the passenger side.

As was said above, upstream O2s should change pretty rapidly over a few seconds while the downstream should change slowly over the same period and the readings should not be the same.

 

i have 107k on it, i just bought the truck last year and the light has been on since I got it; i bought it from a used car lot and the guy that owned the lot drove it as his vehicle and was very familiar with rovers and ordered the ABS wire and cleared the amigos after i installed it. he suspected it was the o2 sensor and since I had over 100k on it I figured it was time to change them. My inspection is due soon so I need to get this taken care before that can happen.