My information was skewed and, I realized, the sources don't mention any sources except other similar sources, so it's a loop of misinformation. I apologize for this continued spread of incorrect data, and I dug into it last night. Dealers are likely the cause of this reported warranty violation.
January 2nd of this year, a member of the Maverick Truck Club said, "I got confirmation from the dealer that disabling the TCU will void the warranty". That was immediately pointed out as being in the dealer's best interests, though it was claimed that the dealer went back on that claim and "would do some research".
Under Magnuson-Moss, the FTC says a company can't void a warranty solely because of unauthorized parts or service; the modification has to be shown to cause the failure. I found nothing saying disabling a modem is illegal, and no "user, not owner" clause. If anyone has a real source, or if your own dealer purchase agreement indicates anything like this, I'd love to know.
What I did find, however, when I dug into the telematics/data question from this thread: the real issue is the manufacturer's verbiage and owner requirements in their privacy policies.
Per Ford's connected vehicle privacy notice (effective July 1, 2026), the modem talks to the cellular carrier unless it's deactivated or connectivity is disabled, and some model-year 2020+ vehicles send analytics/diagnostic data from delivery. Modem messages identify the vehicle, SIM, and modem serial number. Turning off radios on your phone does nothing to the car's modem. (Ford also says vehicle location can be derived from a phone paired by Bluetooth or tether.)
Ford's privacy notice lists service providers, dealers, marketing partners, and ad companies, and some of that can count as a "sale" under state-law definitions. It may also disclose de-identified connected-vehicle data to others. On insurance, Ford said in 2024 that the in-car insurance data setting is off by default and that it doesn't send connected vehicle data to LexisNexis or Verisk. I found no evidence of Ford selling driving data to insurers, but there are allusions to the data being available to law enforcement. Now, a policy shows what a company says it
may do, not what it
does. Models and states differ.
I did find the California privacy agency v. Ford: $375,703 fined in March of this year for requiring email verification before processing opt-outs, but not for selling driving data.
In fact, GM got hit harder for their actions (FTC v. GM): In an order finalized Jan 14, 2026, GM allegedly collected and sold precise location and driving data without informed consent. The FTC placed a five-year ban on giving that data to consumer reporting agencies, plus 20 years of consent/opt-out requirements.
This data assumes the owner has not sold the vehicle, and will continue to associate with the previous owner if you don't go into In-vehicle privacy/connectivity settings and perform a master reset if you buy used or perform a modem deactivation (remove the modem). A ranger5g member cut power to the telematics module (fuse #9), but because of that you lose remote start and remote find.
A lot of vehicles make this process intentionally difficult and the drawbacks mostly remove modern conveniences in a privacy tradeoff. I found a Rav4World post that shows on 5th Gen Rav4's that the Bluetooth function is disabled when removing the DCM (data communication module).
You can ask Ford what they hold on you (rights vary by state), and request a free LexisNexis consumer disclosure once a year as well to verify Ford's claims. All this is to say that,
@4x4junkie is right about most of it. I'll go ahead and add that there
can be situations where pulling the fuse continues to broadcast data, though I'm not sure about Ford specifically, and what data is broadcast may be limited to.
- GM: service guidance says the backup battery powers the telematics module so an emergency call can still be made after the main battery is disabled. It may be built into the telematics module itself. GM's guidance also warns against pulling the OnStar fuse unless the ignition is OFF, because of this design.
- Toyota/Lexus: some models have a backup battery that's part of the DCM (Telematics Transceiver). Toyota calls it the Back-up Battery, Mayday battery, or Mobilephone battery.
- Volvo has one too, and the EU eCall mandate pushes European-market vehicles toward systems that work during and after a crash without the car battery, but that's not specific to the US. It does present further challenges, however.
SOURCES___________________
Backup battery in TCM/TCICM:
https://rts.i-car.com/crn-2278.html
California agency v. Ford:
https://privacy.ca.gov/2026/03/ford...ding-unnecessary-friction-to-opt-out-process/
EU eCall requirements:
https://www.mouser.lt/pdfDocs/Four_..._telematics_hardware_in_the_connected_car.pdf
Ford statement on insurance data sharing (via Ford Authority, March 2024):
https://fordauthority.com/2024/03/ford-issues-statement-on-data-privacy-sharing-amid-concerns/
Ford connected vehicle notice:
https://www.ford.com/help/privacy/connected-vehicle/
FTC GM order:
https://www.ftc.gov/news-events/new...ected-sold-geolocation-data-without-consumers
FTC on warranties and aftermarket parts:
https://www.ftc.gov/node/54283
GM backup battery / fuse guidance:
https://rts.i-car.com/collision-repair-news/backup-batteries-and-main-battery-disconnect.html
LexisNexis consumer request:
https://consumer.risk.lexisnexis.com
Maverick Forum dealer post:
https://www.mavericktruckclub.com/f...elematics-void-the-warranty.59244/post-998092
Rav4World forum thread:
https://www.rav4world.com/threads/how-to-fully-disable-telemetry-and-have-an-air-gapped-car.343029/
Toyota/Lexus DCM backup battery:
https://rts.i-car.com/crn-2377.html
Volvo backup battery:
https://volvocars.com/en-ca/support/car/s60/article/7d2f769f8cef9620c0a801514256de31