There is a B2AAA code that is a pending catalytic converter failure code (forget what it correlates to, P04....). Most likely it is a failed post CAT O2 sensor. Are you throwing other codes? Is the car otherwise running fine? Some other codes related to this would be:
P0036
P0138
P0140
P0141

If your sensor is bad, then the ECU is also going to report a bad CAT or a pending CAT failure.