We need an online guide, based on make and model, on how to disable the transmission of this data.

The situation here is rather bleak really.

Generally these cars have their own always on cellular data connection paid by the manufacturer. So they don't depend on. Your phone for anything.

What they do is record and transmit any sensor data they can. The sexual activity you mentioned, comes from the sensors in the seats that are required to activate seatbelt warnings, or disable the airbags if a child is in the seat. Data from those pressure sensors can be used to determine if there's a certain kind of rhythmic motion happening in a given seat.

They also collect any and all data they can from devices they connect to. Like phones. So don't use carplay, or android auto. Don't use their app. When using Bluetooth audio don't give permissions to make calls or access contacts.

It should be possible to physically disable the onboard cellular radio. That will prevent any live data tracking. Exactly how depends on the specific car you're looking at.

I would assume the dealer can access and download the data manually. Use private non-dealer repair shops for any regular maintance or any repairs possible.

Drive older cars and learn how to fix them!

Not the exact (and only) solution, but some manufacturers may have a Do Not Sell My Information request form. Subaru has it on their website and I submitted a request for myself. Obviously we won’t know if they actually follow through, but it’s worth a shot. Some people have experimented with going in and actually disabling the antenna that the car uses for telemetry, but that’s at your own risk and likely voiding warranties in the process.

I think using carplay/android auto isn’t as bad since the infotainment system is just projecting your phone’s display, so your phone’s privacy policies apply. Whether you trust those policies is of course up to you. Cars that force their own systems (like GMC I think) are more risky because you are using it directly.

Off topic. I saw a few comments about disabling or removing the modem on the car. How about removing where the telementry code resides in? Is that feasible?

Number 1) find the fuse that controls the modem and pull it. Without this your car can only report when the service techs hook it up to their diagnostics, and what is reported there versus what reports on the regular from the modem is a huge difference. You lose a lot of convenience this way, but that’s to be expected. CarPlay and auto give you a lot of that convenience back, but now you’re giving a lot of that same data to Apple and Google, even if all you think you’re doing is projecting maps from your phone to your infotainment. Do you trust them? You can use Bluetooth audio in most cars without using CarPlay or auto, that should be safe. Stick to maps on your phone if you don’t want Google or Apple getting your driving data.

As long as you have a Google or Apple phone in your pocket... The car will actually not gather much more than your phone already does... So don't overthink it.

You really can't

Also don't start breaking your own car like some of these comments suggest. It can go wrong in many ways and may even harm the value of the car.

I think the only good way to go is to break the transmitter inside the car and hope it doesn't brick it.

This is what you are looking for: https://youtu.be/pA0zYTmi5ck

If buying new, I believe you can ask to have the modem removed from the vehicle, which wouldn't allow your car to access the internet. Haven't had the opportunity to try this myself yet, but very much plan on it for whatever vehicle I purchase new in the future.