I just installed an O/R jba x-pipe. I got check engine light on (of course no cats!) so my tuner can disable this rear sensor, i would like to know if it s safe to disable it...
rear O² sensors weren t used to correct air fuel ratio? If disabled, the ecu will not be able to provide right mix?

 

Ya, rear O2 sensors aren't needed for a/f mixture. If ur tuner can turn them off then do it. But the front O2 sensors are needed.

 

Here is an article that explains it pretty well:

http://www.tricktuners.com/code_names.htm

In short, like Irish said, you do not need the rear O2's working to get the right A/F mixture, the rear O2's just monitor the cats to make sure they are working . . . which of course they are not in your case

 

Thank you guys!

 

http://www.bigdaddiesgarage.com/mini-cat-cel-fix.html
Just saw this

 

I put a non fouler thing to avoid cel but it doesn t work. I finally removed it with my tuner.