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HOWTO: Disable DCM (data transmission) in Lexus GX460 2022 (and earlier model years)
UPDATE 4/30/2022: Unfortunately the original method cannot be made to work. However, there is an alternative solution, which is a lot simpler and which should be good enough for the vast majority of people, who are concerned about their privacy. See below in this thread.
UPDATE 4/13/2022: The original solution below is not good enough to prevent the DCM from receiving the network signal (and thus from having DCM to transmit). The DCM case is plastic, not metal, and while there is apparently no dedicated antenna inside the DCM case, there is still enough parasitic signal leakage through the case to be picked up by PCB wires resulting in DCM showing 1-2 bars of signals in the areas with good cellular coverage. See below in this thread for an updated solution.
ORIGINAL:
It has already been pointed out here (link) that your Lexus (and likely not just Lexus, but every other car brand too) is spying on you by transmitting your GPS location, driving data, screenshots of the entertainment screen, etc. over an embedded cellular modem. The same cellular connection also allows 3rd parties to remotely start (and stop!) your vehicle. Yes, we’re headed to the dystopian “Minority report”-style future, where peasants will have no privacy and will be happy. If you’re comfortable with this brave new world, you may disregard this thread. If you’re concerned but are still too lazy to turn both GPS and WiFi in your mobile phone off (and to make a habit of turning any of those on only when needed) then you can also disregard this thread, as the Lexus spying is then the least of your problems. For those remaining few who are hardcore enough to not serve as enablers for the brave new world, here’s what can be done to save both your privacy and your karma.
The easy way
Install Toyota mobile app, register your vehicle and then somewhere in the account settings select the option to not share your vehicle data. This will (hopefully!) stop the spying. This will not disable the mobile connection itself, thus still allowing for 3rd parties to control your car. This option did nothing for me as the mobile app refused to register my brand new Lexus, complaining that it didn’t match the records which Lexus already had on me. There was an option there to call Lexus and to sort it out, but I didn’t bother.
The “angry peasant” way
We are lucky to still be in the early stages of this privacy war, and so it is still reasonably easy to use brute force against the adversary. The module responsible for maintaining the cellular connection (the “Data Connection Module” or DCM) can still be accessed without having to disassemble the entire car, but by simply removing a few plastic panels. One can speculate that if enough peasants start to disable the connection, the adversary will begin hardening access to the components involved. We are not there yet. Disabling (or, to be more specific, “blinding”) the DCM will require about 90 minutes of one’s time, $12 in tools and $40 in parts. It will however also require the nerve to start prying plastic panels out on your brand new car. The resolve to do this is the hardest part of the job. I was able to do this to my own brand new shiny $60K Lexus, and thus you (or your trusted car mechanic, but likely not your friendly Lexus dealer) can do it too. Here’s how to do it (sorry, it is not as easy as just pulling a fuse out).
Background
Lexus has 2 separate GPS antennas and 2 separate cellular connection antennas. One GPS antenna feeds the navigation/entertainment module, which presumably has its own GPS receiver. The other GPS antenna and both of the cellular antennas feed the DCM. Presumably, DCM has another GPS receiver and either one or 2 cellular modems. The reason it may have 2 cellular modems is because of the original Lexus “Safety Connect” (SOS / MAYDAY) feature which already contained a modem, but presumably it wasn’t originally used for spying. Since it is impossible to tell if there is now a new dedicated cellular modem added solely for spying or that the original MAYDAY one has been repurposed and merely received the second antenna, it was necessary to blind all these antennas vs. for example, trying to blind just the “shark fin” antenna, which might have been somewhat easier to do.
Pre-req
Good quality (Nylon) trim removal plastic tools - $12 on Amazon
SMA male terminators (3x) - $7 on Amazon
FAKRA Z Female to SMA female adapter cable (3x) - $20 on Amazon (break and remove the plastic shroud of the FAKRA connector using small wire cutters, keeping just the internal metal SMB connector; or pull the plastic tab and push the metal connector out)
One month of alldata.com subscription for Lexus GX460 2021 - $16 with a coupon (they do not yet have 2022, the 2021 model is close enough).
The process
Follow the alldata.com “CELLULAR COMMUNICATION: DCM(TELEMATICS TRANSCEIVER): REMOVAL” document. Check out some of the YT videos on how to remove the plastic panels (
). The process is not that hard.
Be careful when removing the “KNEE AIRBAG ASSEMBLY” (see number 8 below), make sure you have access to the 3 bolts which hold it in place. Remove those bolts before prying the assembly out. To disconnect the fancy airbag electrical connector, pull the yellow lock outwards first with a needle. I performed the whole procedure without disconnecting the main car battery, which is probably not the best idea. Also, I avoided starting the car (even into the “accessory” mode for testing) while the airbag was disconnected to avoid logging any failure codes.
Removing the “DOOR SCUFF PLATE” (see number 4) and “COWL SIDE TRIM BOARD” (see number 5) requires applying some moderate force on the clips. The rest of the panels are very easy to remove.
Once you have access to the DCM, unplug the 3 RF connectors (one of those would be GPS, the other 2 are cellular antennas) and replace them with the SMA terminators attached to the FAKRA Z adapter cables. Insert the SMB / Fakra end of the cable into the DCM connector. Tuck the wires nicely to prevent any rattle. I used some non-hardening sticky silicone putty to fill around the SMB connectors to protect against accidental disconnects.
Your DCM will no longer get any GPS or cellular signal, but other than that it will be happy. Your navigation will still get its GPS. All Lexus features which rely on the car having its cellular connection (remote start via the app, remote location, SOS, etc.) will obviously no longer work.
Attach all the panels back. You’re done. Consider reversing this modification in the future before selling the car. Or just be upfront about the mod and charge the buyer extra for privacy.
All this hassle could have been easily avoided if Toyota/Lexus merely allowed the option to turn the cellular modem off in the car config menu. Yet they chose not to do it. Tells you everything you need to know about how the people who control these corporations envision the future for the plebs.
Last edited by PrivacyMod; 04-30-22 at 03:19 PM.
Reason: Another update
I thought DCM can be disabled through the Setup, does it?
unless something changed with 2022 GX, I alway disable the DCM whenever I am in the loaner Lexus from the dealer. Most of time, those are NX, RX, and ES. As a general practice, when I am on the trip and use rental cars (as I do often), I always disable those “Link” function before I drove off. Even different manufacture has its own flavors of names and different setup options, but you can always find them under where associated with connection, hot spot, or Wi-Fi settings.
Great post! Thanks for sharing! I am just a little confused, So that subscription to remove transceiver is that in the dash where you have to take out all of the center console items?? And then you have to do your steps on right side? Any way you can copy and paste how to remove transceiver? Would this also work so they can't remotely shut off your engine in the future with the push button ignition set up. Have you been able to test any RF coming from spots it shouldn't be? I am new on here, can you send me a private message and we can talk more? Would like to talk about a few other issues as well..
Last edited by Whiteoak; 03-23-22 at 09:27 AM.
Reason: Added questions
It tells me that "Whiteoak has chosen not to receive private messages or may not be allowed to receive private messages".
Anyway, there is no need to mess with the center console (those YT videos are taking it out as they need to replace the entertainment module. We don't need that. I linked those videos just so people could get a feel of how to remove the panels. I have never done it myself before and was very hesitant. Turns out it is not that hard.) There is also no need to take the DCM module out, one just needs access to it, which is why we need to remove the right side. Sorry, I won't be copy-pasting the document from Alldata on how to remove the transceiver, this would very likely be in violation of AllData rules. I am sure any Lexus owner can afford $16 to get that document. It is well worth the price as it shows locations of all plastic clips under each of the panels, so one then has a better idea of where to pry them.
No, I didn't measure any side-channel RF. I doubt there's the 3rd antenna inside the DCM module itself. This would be a design overkill, given the minuscule number of hardcore Lexus owners who will bother to mess with their external DCM antennas per above (and those who do mess with it will not hesitate to open up the DCM module and cut the internal antenna out too. In fact, this was my original plan before I found out the suitable external RF connectors to fit the DCM).
This will disable remote control via the cellular link. It won't disable short-range remote control via the keyfob link. I am not very concerned about the latter (as at this point they may as well shoot you ).
Maybe because I just opened an account on here.. Do you have a picture of the DCM? I am just confused then why running those new cords would shut it off.. What step am I missing with the DCM? I doubt the wires have a shut off relay? I have been considering a new GX, haven't bought one yet because Not sure if I wanted to wait an extra year or two for redesign or not. But my wife's toyota I wanted to do this to. Sorry if I am being a hassle, how does this work to disconnect antenna with just those cords installed? Is something else needed to do to the DCM To deactivate the signal? I know the world we are coming into they want it a little like demolition man. Cars that can be shut off whenever they want. Automatic braking that can be remotely controlled. etc.. Self driving.. Robotic world. I don't even like automatic braking, I know at the moment you can shut it off on the car, but anything with bluetooth can link and remotely activate it. They are using every device with bluetooth to eventually link in with the entire 5g grid.. Privacy is only one issue.. Major health issues from constant high levels of RF Radiation.
...why running those new cords would shut it off.. What step am I missing with the DCM? I doubt the wires have a shut off relay?
It's because we are disconnecting all 3 antennas from the DCM (and replacing those antennas with properly terminated sections of a coax cable). There will be no GPS signal and no incoming cellular signal. And the cellular modem is not supposed to transmit anything when it can't detect any cellular network. And even if it does decide to transmit, the transmitted signal will just all get converted into heat in that 2 watt terminator.
In theory one could just disconnect the 3 original antenna wires and then either keep the connectors open or short-circuit them with a suitable shunt. Both of these options are not ideal though. The connector left open may still allow for some small signal to feed in (follow the very first link in the OP, the guy who tried this open connector option on his 4Runner noticed that the DCM was then still showing a 1 bar signal when passing near cell towers). The short-circuited connector may in turn result in the transmitter electronics damage (because of a reflected wave) if the transmitter ever decides to transmit anything. Hence we're going with using properly terminated RF coax sections.
Thanks I just ordered the wrong RP-SMA termination, realized it doesn't have the wire in the middle.. Do those termination leads just sit out like your picture or do they plug into the right lower piece? Just asking because the only SMA ones I can find on ebay have a lot shorter termination end instead of your long ones.
I think it is illegal to tamper with the EDU AKA black box.. Car insurance can even cancel your policy for doing so. That is only used for insurance in accidents and police info. Doesn't transmit data unless they take it out and recover it.. I think it became standard law that all cars 2014 and newer to have to have the black box..
Last edited by Whiteoak; 03-25-22 at 01:45 PM.
Reason: Edit
Do those termination leads just sit out like your picture or do they plug into the right lower piece? Just asking because the only SMA ones I can find on ebay have a lot shorter termination end instead of your long ones.
The terminators are electronic components (they have a 50 Ohm resistor inside), they do need to connect to the coax cable section properly. The specific connector polarity doesn't matter - can be male terminator SMA to female coax SMA or vice versa. I just used whatever was available at Amazon with quick delivery:
My original plan was to use the SMA to SMB adapters with the SMA terminators, and thus to avoid the coax cable altogether (you can see those adapters pictured in the OP and crossed out), turned out these adapters are too short and too thick to fit into the DCM RF connectors. Hence I ended up having to use coax cable adapters.
Thanks for all your help. So pretty much you disconnect 2 or 3 wires from the DCM and attach ones that don't send a live signal.. So do you even need the alldata thing to do this?
Someone has already shared a link to another thread, which shows pretty much the same info as can be found in alldata (how to pry the plastic panels correctly). No need to order alldata.
UPDATE 4/13/2022: Turns out the original solution above is not good enough to prevent the DCM from receiving the network signal (and thus from having DCM to transmit). The DCM case is plastic, not metal, and while there is apparently no dedicated antenna inside the DCM case, there is still enough parasitic signal leakage through the case to be picked up by PCB traces resulting in DCM showing 1-2 bars of signals in the areas with good cellular coverage. Here’s the updated solution which seems to work a lot better:
- Do not bother with Fakra Z cables and SMA terminators.
- Once you got access to the DCM, disconnect all the cables attached to it, and then remove the DCM itself.
Remove the 2 side mounting brackets from the DCM case and then wrap the case in 2 layers of aluminum foil. Use Scotch tape to help the foil wrap nicely. Attach the side brackets back making sure the machine screws press through the foil. There needs to be electrical contact between the foil and the ground of the DCM module. The side brackets are connected to ground and so is the top metal plate of the DCM case. Make sure the foil is in good contact with those.
Put the DCM unit back, attach all the cables, except for the 3 RF cables mentioned in the original procedure. Do not connect anything into the 3 RF connectors. Instead wrap the foil on top of them, covering them completely. Fix the foil with Scotch tape. Press the open foil edges around the existing cable wires as best as feasible. The goal is to leave as little open areas as possible.
Put back all the panels. This is it.
I tested this solution in the same area where the original fix was still giving me 2 bars of DCM signal. This was producing none.
For those curious, I did open up the DCM module, hoping to maybe find a physical SIM card there. Unfortunately there wasn’t one, not even inside of that Kyocera module.
See, a tin foil hat can indeed be helpful when applied properly.
03-22-22, 04:24 PM
HOWTO: Disable DCM (data transmission) in Lexus GX460 2022 (and earlier model years)
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