I just used my temporary spare also - ran over some roadside debris, and I have to say that both the tire pressure warning system worked great and the Eagle RS-A held air with a big puncture in the sidewall for nearly 18 hours. Wow.
The mini-spare had only 18 pounds of air pressure therein when I mounted it, but after limping to the neighborhood Exxon, it held air for two days while I got another tire.
BTW, if you need a replacement Eagle RS-A - it'* all about Discount Tire. $176 plus M&B and tax. A GREAT deal, since the Goodyear store wanted $315 and everyone else was in the $240 range.
Recommendation - check your mini-spare to make sure it'* in the trunk and carries the right air pressure.
Recommendation II - after you get a low tire pressure warning, you clear it by selecting it on the display and then holding the reset button for fiveish seconds. The low pressure warning drove me crazy for three days until I opened up the manual and found salvation.