One more believer here:
I was following this post because MY pressure light went on as well. Tried checking the air at the gas station ~ all seemed fine. Added air to one tire that 'looked' low, but light remained on. Last night, went to store & bought 'reliable' air guage and tires read: 30, 31,31,32. Brought them all up to 35 by the new guage ~ presto. W/in .4 miles of driving after refill, pressure light goes out.