hi, just want to ask, i am getting codes P2254 and P0420 on my 2013 mazda cx9.
I have checked the fuel trims and it shows like this.
Fuel trim(long) B1=-0.8%
Fuel trim (short) B1= 0.8%
Fuel trim (long) B2= -3.1%
Fuel trim(short) B2= 3.1%
I think i changed the O2 sensor recently on Bank2, the one in front of the car. What do you think is the problem and possible fix on this? thank you and more power!
Fuel trims looks really good. what you need is a graph of your O2 data
Those fuel trims don't look terribly bad but obviously the closer you can get LTFT to zero the better. (Bank 2 is running a little rich.) The P0420 may be due to the O2 sensor problem indicated by P2254. You can find diagnostic information here:
https://www.obd-codes.com/p2254
but i just change O2 sensor on bank2, i am not sure about what could be the problem.
Did you use an OEM sensor or aftermarket?
The link provided has detailed troubleshooting information you can use to help find the source of the problem.