I know someone who is in engineering at one of the big Auto makers, we where discussing this issue and the person told me that even if you remove the SIM (disable cellular internet) The dealer we still upload all the data from the “black box” to the auto maker when they connect to OBD / CAN diagnostic port in your car during service. The manufacturer’s service software just does that now the tech does not even have to initiate it. Also some dealers can automatically connect using RF to your car as soon as you enter their lot, This can be by Bluetooth, WiFi, and/or the CAN bus via the keyless entry module or TPM (Tire Pressure Monitor). There was an issue a several years ago with hackers gaining access to Jeeps while on the road via RF.
So software is running on your car that desprately tries to extract and sent your peronal information to its command and control server.
I was going to say "be stingy with access to the OBD / CAN port" but if wireless is involved then avoid the beacon (its wireless and tucked away in a corner so you dont know if its there) or get your data stolen. I feel violated.
It gets worse, Auto makers are now building cars with options in them that require an online subscription and disabling access for more than x time will shut off the option(Tesla, BMW, and others do this now). There is talk about putting the car in “Limp home” mode if access is cut (Car will only have 35mph max speed and limited functions, no HVAC, no Radio, etc.)
Isn’t this solved by having your car serviced with an independent mechanic? The only catch is warranty work, which is pretty unavoidable unless you’re willing to pay for repairs in lieu of free ones.
A lot of independent mechanics will use the manufacturer scan tool and service applications or use a 3rd party scan tool/applications that is licensed through the manufacturer and still uploads the data.
For my Ford, the manual was very helpful. Taking a look at the fuse box diagram, I was able to remove the fuse for the modem.
Thankfully I was able to verify that the modem power was secured because when I enter the infotainment settings to view the modem serial number, I can no longer see the modem serial number. It is just blank.
This won't work for all vehicles because the modem may have the same fuse as critical equipment.