OP: When you get the warning after several days, are the tire pressures still all where you set them, if you use the same gauge? And only check cold, not warm

Note that it is a wheel-speed sensor system, not a pressure sender 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