TPMS light stayed on the whole way home, checked tires at home, between 30 and 34 PSI. Recommended value is 30, so it's all pretty okay - obviously, everything was warmed up from driving.
Inflate to sidewall and drive 130km/hr for six hours. Evacuate to 1 micron, hold for 20 hours, break vacuum with pure argon, re-inflate to 33 1/3 psig. Drive 78km/hr for 16km. That should fix the yellow fleabag light for good.
lolwut
Inflate to sidewall --> yellow fleabag light
Fleabag was absolutely certain that the proper tire pressure for anyone anywhere for any vehicle was printed on the sidewall of the tire.