UPDATE (finally): had at least one dead sensor for past couple years. A few months ago, had my tire guy install 4 new sensors ("aftermarket" Napa part # 92-1016C) along w/2 new tires. Per the chart on this thread, they are the 433mhz. Finally hooked up w/Chrysler Tech & a working DRB111 & trained to car computer; No more warning light (so far). (Napa part on the same chart line with Schrader 20028)

With all 4 new sensors, I think car may recognize either frequency, not sure. Car is 2005 Roadster Limited, manufacture date: 07/04.