It isn't a problem with the sensors, it is a problem with your tire pressures. Be glad that you get an alert. I would keep a tire pressure gauge in the glovebox, so that you can quickly determine if you have a very low tire, or a marginally low set of tires.

Bottom line is, it is an alert system and not an inflation system.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue