[poly_morphis]

Take Volkswagen vehicles (VW/Audi, mainly). Nearly every electronic module in the car that you'd want to replace has component protection, making it literally impossible for a non-dealer to replace it since you need access to VAG servers to get the token to code the module for the car VIN. I had this experience recently with a CAN bus controller module that just randomly failed. $3k at the dealer. I would have preferred to do it myself but there is no way.

[bzzzt]

VW didn't key components for a long time, but a VW Golf was uninsurable in certain cities in the Netherlands because airbags and navigation units were stolen multiple times per year in some instances. Sometimes the thieves waited just a few weeks until most cars in a neighborhood had replaced the stolen components and made another run...

[hn_acc1]

I couldn't believe it when my wife's '16 GTI (base) needed a new battery, and I realized for non-base models, the BATTERY is coded and needs dealer programming to be replaced.

Our '08 Caravan had the ABS module die, and try as I might with 3 or 4 independent mechanics, had to go back to Dodge/FCA to get it reprogrammed for the car to accept the new module.

[poly_morphis]

Yes, the battery needs coding to tell the car about its capacity, battery type, etc. to optimize the charging. Fortunately coding modules is not completely locked behind dealer-only tools (see VCDS https://www.ross-tech.com/vag-com/VCDS.php), but it is very inconvenient for the non-enthusiast who probably doesn't want to spend $200 on a tool to code their battery.

[bluGill]

That is about theft. Chop shops won't steel the car for the ABS module.