TPMS Indicator light came on this morning. Tires not flat. Took to Firestone to have them check the pressure. Pressure for the two front tires was a little low at 30 and the back was where they needed to be at 36. They brought the two front tires up to 32 for me and when I got in the car the TPMS indicator was still lit. I drove the car about 10 miles to see if that would get it to pick it up but no luck. When I returned to my office I went through the process to reset the indicator; again with no luck;it is still lit. Any ideas?