TG101

The tire sensor light came on my Lexus yesterday after the temperature droppped to 27 degrees. I checked the tires and filled them to 30 psi as listed on the door panel. THis did not fix the problem. I stopped by a local tire center and was advised to fill tos 34 psi and i did. I was told to drive it a bit and the problem would go away. It did not. The selction was set to MAIN and I tried the reset button with no luck. This morning it set all tires and spare to 30 PSI and pushed the reset button still no luck. To these valves possibly have a batter that may need to be replaced or is one or all of the sensors bad? This is an irritating problem. Can anyone offer some suggestions on what more can be done?