Trying to figure out what’s wrong. I have replaced the bank two sensor to twice.
And it reads bad again.
After resetting the light and driving it, the voltage isn’t acting right on that sensor the b1s1, b1s2 and b2s1 voltages all vary while you’re driving it but the b2s2 is erratic.
all sensors look good when replaced. Not burnt or weird oxidation or residue.
car runs fine and if not for the light would never know anything. Idles fine, starts and runs good, mileage ok.
2013 cx9 140000 miles.

 

What brand sensor are you using?

What fault codes are you getting?

What diagnosis are you doing?

Have you monitored the short & long term fuel trim?