> I would presume that other manufacturers might have this as well.

On newer vdubs there’s both a “location services” and a “offline mode” toggle in the infotainment, though this only turns the infotainment SIM off. Obviously this also disables remotely controlling the car using the app.

And the secondary eCall SIM cannot be disabled - not without triggering a fault code and a tell-tale. Since eCall is considered a safety-critical system it has self-monitoring and must work for the vehicle to pass inspection. It even has its own separate power supply. This is true for any vehicle (type) newer than ~2018 in the EU. This probably makes tracking the rough location of any eCall-equipped vehicle quite easy, if you have signaling-level access to the cell network – exactly like in all those SS7 exploits.

edit: turns out they thought about that and eCall modules aren’t supposed to constantly stay connected to a cellular network (dormant mode). Instead they only log onto the cellular network when needed. Difficult to verify as a consumer though.