The Engine Control Module (ECM) monitors the switching frequency ratio of heated oxygen sensors 1 (front O2 sensor) and heated oxygen sensors 2 (rear O2
www.engine-codes.com
According to the link above, it could also be a dirty air filter or an O2 sensor. Those are certainly cheaper. I’d check the air filter myself real quick, should only take a minute to make sure it’s not dirty. It shouldn’t be hard to check the O2 sensors yourself either. You’ll have to get under the car, unplug the sensors and read their resistance with a voltmeter. I’ll have to look up later what the resistance should be, unless you search it out yourself or someone else here knows off the top of their head.
If all those are alright, then yeah, it’s gonna be the bank 1 catalytic converter (and it probably is I’m sorry to say). In that case, don’t go to Infiniti unless you want to sell your fist born! Go to a local muffler shop and tell them you need a catalytic converter. Unless your warranty covers it, it’ll still hurt, but Infiniti will buttfuck your soul over it.