Do I assume PO3E Bank 1 sensor 2 to be the secondary or lower sensor?

installed over a year ago but just getting to running checks.
999426 miles
where is the hidden button to get into the settings menu?
there is a thread I believe?

 

If you don't have the BMW proprietary codes, you can scan the car in "global" OBDII; these codes are more useful for the DIY community. When it comes to O2 sensors, there is only one bank in a MINI since it's a 4 cylinder, so Bank 1 sensor 1 is the upstream sensor (before the cat), and bank 1 sensor 2 is the downstream sensor (after the cat). Bank 1 sensors are wide-band sensors on this car, and Bank 2 sensors are narrow-band sensors. Make sure you are using an OEM O2 sensor on MINIs! The engine computer doesn't like to talk to strange O2 sensors.

 

Maybe that is it they are not OEM so both were replaced but I will get OEM sensors.
thnx

 

Is there a way to unplug the bottom & top O2 sensors easily I am thinking it may be best to unbolt the fwd frame & gain a couple of inches?
when I installed these everything was apart so easier.
The bottom sensor as it is a plug in a wire will need to study that connection?
going to get OEM sensors.

 

The top O2 sensor I believe is different aftermarket versus OEM #1 on R.

the lower appears similar but not at 200$ for aftermarket & 700$ OEM #2. On R.
& OEM they come pre anti seize applied so none gets on the sensor.