New information...
I've discovered that OBD-2 does codes that are pending do not illuminate CEL.
However, shouldn't something like P2270 immediately make themselves visible almost right away? I mean, it could be the sign of a malfunctioning O2 sensor and I imagine that would stay on for more than two cycles.
Also if you "clear" it, does it still have a pending status? We did clear it and it came back pending.
I do live in Texas where weather can go from 70F to 30F in a literal day...I figured the ECU freaked out when it saw the change in sudden air density and made it run lean for a bit because more air was coming in. Or I could be talking out of my ass trying to figure out why this code is pending.