Remove Modem/SimCard from a Car

rabiddolphin , 5 months ago

Don't use a jamming device that'd be effective, wrong and illegal

Tzeentch , 5 months ago

Your best bet is to find a car where its easiest to disable the antenna/cellular modem for, so look for a car that has a fuse for the DCM(digital communications module) you can pull, as having it be a fuse means you can readily reconnect it should you need to, try to find its schematic online, or find the repair manual for the car or use a car maintenance program,

Apparently its also possible to call the car company and ask for an opt out when serviced,

I vaguely remember some people experimenting with replacing the head unit with aftermarket ones, but no idea how well that would actually go in practice

Lemonparty , 5 months ago

I vaguely remember some people experimenting with replacing the head unit with aftermarket ones, but no idea how well that would actually go in practice

This varies wildly from manufacturer to manufacturer and even year to year. For example, GM cars used to route damn near everything through the entertainment unit, so that was your central computer. Cell antenna, on star control panel, every that phoned home. That was as recently as mid 2010s. It also led to hilarious problems where a relatively simple issue like an OnStar button not working well required a complete replacement of the stereo unit (which was $8k or so in parts and labor). Now that instrument clusters are doing more while also getting more diagnostic and digital, things are transitioning to a more centralized computing system somewhere else. This can make it easier OR more difficult to get around, depends on design.

For other brands it's borderline impossible to even use an aftermarket system. Mazdas for example the entire infotainment system relies on itself. There's nowhere to even put a traditional aftermarket. I'm sure it's possible, but the design of the interior is completely based around the infotainment unit.

Reality_Suit , 5 months ago

I am never buying a new car again. It will be hard, but I'm only buying old cars and repairing them. Not sure what to do about fuel when that stops. I Not sure about how to deal with a lot in the future, but I'm going to keep trying.

bluGill , 5 months ago

You can have good luck just by buying 10 year old cars - they might have connectivity, but the it will be to a cell/network standard that no longer exists and so for practical purposes the car cannot connect to anything.

BearOfaTime , 5 months ago

3G still exists exactly for monitoring services, just not for consumer use.

Milions (billions?) of remote monitoring devices rely on it, like oil fields, water systems, gas systems, etc.

I'm not sure if the automotive systems fall into that, but I could see the manufacturers making sure they were.

I have a vehicle with 3G that always has 5 bars, even when my phone has little or none. Kind of says a lot about the QOS the automotive industry gets.

scottmeme , 5 months ago

Speaking as someone who worked for a corporate auto maker, it won't be an easy task since they try to make it as difficult as possible to disable online activation if even providing the ability at all.

The only real solution is pulling the head unit and trying to find any modem and desolder it, which who knows if it would function as it had before hand since everything is integrated.

It will also hurt resale value.

BearOfaTime , 5 months ago

Or just put a power test attentuator on the antenna output.

It essentially absorbs the RF from the antenna and radiates it as heat. Since cell is pretty low power (1/2 watt max, IIRC), and a cell radio will stop trying to transmit after a while (though it will try again), I don't think it would cause any problems.

But I'm not an RF engineer.

scottmeme , 5 months ago

The newer cars from the company I worked for were always trying to phone home, not sure about other companies but this one was trying to lock you into the online ecosystem.

Darkassassin07 , 5 months ago

While this seems like a great plan; I wouldn't put it past manufacturers to throw an error message and disable the vehicle for 'safety' when it detects a missing network connection for an extended period and/or disabled hardware during self-test.

I hate this dystopian hellscape :(

0xtero , 5 months ago

When I was last working in the automotive industry about two decades ago, a lot of effort was being put into protecting BIOS on diagnostic laptops, so that only "authentic" manufacturer diagnostic tools could be used to service the vehicles.

Pretty sure that development has continued.