alt Hacker NewsTPMS (tire pressure monitoring system) is a coin battery powered computer inside each tyre of your car. They’ve been around for a couple of decades now. Even the lowest end cars have TPMS in each wheel. If you change wheels you need to go to a wheel shop and have them re pair (as in re pair wifi) the wheel with your car. I had to do this recently with my 2014 ford focus.
Anyway those are just four of hundreds of computers in your car these days.
Not exactly a great example as it's unnecessary and expensive to replace. Lots of other microprocessors actually make your car easier and safer to drive.