My 2010 Prius has chronic malfunction of passenger air bag and seat belt warning system. “Air bag off” light stays on all the time, and seat belt unfastened warning light flashes constantly, whether seat is occupied and seat belt is fastened or not. One dealership replaced weight sensor in seat cushion several times, and another dealer replaced the “occupant detection ECU.” The “fixes” worked for anywhere from a month down to a day. I’ve told them either fix it, or give me another car, or I’m going to go to Honda dealer and dump the Prius in favor of an Insight (Honda’s similarly-sized hybrid).
This is what warranties are for. Keep going back to the Toyota dealer.
You may want to check out the “Lemon Laws” in your state and see if your Prius qualifies, or will soon qualify.
You’ll lose a bundle if you trade it.