Trouble with TPMS sensors

[racing5k]

I have read through other TPMS topic threads and can't find my exact issue. I have had the solid light for a few months now and took it back to the tire shop and had it re-programmed a couple of times. Each time the sensors all respond through the horn correctly and the light resets. Unfortunately as I drive home the light comes back on. The only conclusion anyone can come up with is the the watch batteries inside the sensors are just to weak to send the proper strength signal to the control.
This puts me in a though spot because I would like to sell the car, and I don't want to sell it with this malfunction but on the other hand it's almost $250 with tax to fix!!!. The tire shop says I can't replace the battery in a perfectly good sensor, and this really makes me mad since it's a federal law! Let me know if you have any idea if I can replace these batteries.

[viciousvîc]

battery can be desoldered n a new batt soldered back. any other way besides replacing tpms is a federal offense to sell vehicle without a functioning tpms system