In Spain they soon will require V16 [0] too. Originally it was just a flashing light but then it was improved to use mobile networks to send an emergency call to authorities. And proving, that technically, it is possible to have something like ECall without deep integration into the car.
No need of having always on connection to the network, enable on emergencies only. Thus no remote hacking of SIM/base band possible at random times, or broadcasting presence until used. Mechanic or user can check battery periodically, replace if low, just like refilling wiper fluid. Car could even cut all other electric systems after deploying the integrated autonomous V16-like system.
Car manufacturers deciding to make their ECall implementations complex and privacy invading was their choice.
That's difficult because both will need to use the cell network.
But I guess you mean on the car side like two modems? Yeah that would be nice, or at least to mandate the option to turn all manufacturer telemetry completely off. The EU never bothered to do this for computers and phones either though.
I know, and they can be hacked too through sms messages.
But the sim card doesn't have access to the car telemetry. Probably even the whole baseband module doesn't. It just gets that data to transmit when an accident happens.
The worst you could do by hacking the SIM is to make the modem send nearby cell data somewhere. Which is serious enough because the rough location can be derived from it. But it's a far cry from what these manufacturers collect.
Just enable it by default and put a warning in big red letters that disabling the cellular modem will also disable the ECall system, which may mean you might not get the emergency assistance you need and therefore die.
That shouldn't have to be linked. You should be able to turn off manufacturer telemetry while keeping ecall. Ecall doesn't even talk to the manufacturer. It just calls the emergency services directly.
Of course when the modem is on you can't be sure that it's not doing that but that's what we have laws for.
AFAIK ECall uses a voice call with data encoded on the audio channel. This is not what telemetry does, it should be doable to leave the voice channel and disable any data connections. (But it's probably very hard to check for someone who has no background in emebedded systems). Plus, in theory an emergency call can be done without even using a SIM card, right (if network allows)?
https://en.m.wikipedia.org/wiki/ECall