Simpler solution for disabling the DCM telematics - Silencing Antennas

Perhaps you would like to try just disconnecting the antennas. See my post #162 it details my theory.

 

I’m dying to know if this is a viable solution. I’m just too much of a coward to try it myself

 

Thanks for the number, saved a lot of scrolling. So if I’m understanding your post correctly:

pull passenger side dash to access DCM. (I know how to do this part)
Unplug all antenna outputs from DCM.
remove it.
Take out the SIM card from it.
Unplug the backup battery from it.

leave it there and it’s now a useless brick that transmits nothing?

hope that’s right, I can (and have) built a beautiful craftsman home from scratch but have never ventured into vehicle electronics, computers, or anything of the sort so this is new to me. I HATE remote connectivity that can be hacked (happened to me already) or shut off remotely. Thanks for the help

 

Well, actually I directed you to Post #162 was about this mostly:
"It may be all that is needed to deactivate the DCM is to disconnect the antennas with "no" termination. My intuition says that the DCM detects disconnected antennas so it does not self-destruct trying to transmit into an unterminated output. It may turn out the OP altitude-nerd was too good at what he was doing, and the trouble started because he knew GOOD engineering practice of terminating Radio Frequency outputs; what may be needed is BAD technician practice the DCM detects and deactivates itself."

"The disconnection of the Telephone antennas from the DCM module still needs to be "tested" to see if it does indeed deactivate the DCM from transmitting to Toyota. Disgruntled Scientist I believe would be a great candidate for this test.

Another test would be to Short out the Antenna plugs and see if the module sends a "Shorted Antenna Circuit" code to TechStream. This "Shorting" would be even more imperative that the DCM deactivate itself to avoid self-destruction due to a transmission."

You seem to say that you want nothing at all to do with the DCM module. If that is true the "testing" of just disconnecting the antennas still hasn't been tested to my knowledge to see if the deactivation is that easy to do.

Now, for myself I have left everything connected and just removed the SIM card - thus no cellular transmissions. The unit is still powered which means I still have the microphone and the meager communications between the DCM and the radio. By "meager" I have just discovered that the USB connection between the two units does do something: It puts the diagonal bar across the DCM signal strength bars in the upper right-hand corner of the radio display. It may do more.

The SIM card removal I do not recommend for those inexperienced in electronics and surface mount soldering. Besides disconnecting the DCM internal battery this is all I have done to my unit. All other fuses, cables are intact and everything else seems to be working.

Remove the SIM card from your phone and you have no cellular is my way of thinking about it. You can still use the Wi-Fi and Bluetooth on your phone without the SIM.

I am not doing anything, that I know of to destroy or harm the DCM unit, as I may be making other plans for it: one is to install my own Data only SIM and use the DCM as a Hot Spot.

 

I completely removed the DCM, rewired the right side speakers and am going to replace the head unit with a Sony. Simply remove it and the truck is off the grid. If you like the original factory head unit just rewire the mic. to it. Now that the DCM is sitting on my coffee table with the battery disconnected, no more odometer mileage updates on the Toyota app and no more communication back to Toyota. I can no longer connect my iPhone to the original head unit as I didn't bother rewiring the microphone, the new Sony head until will have its own microphone.

I don't understand trying to keep the DCM in the truck, why keep it in place?

 

Personally, I'm trying to keep the OEM headunit in place w/ speaker + microphone working. I'm not 'fraid of jumping the mic and pulling the fuse, just lazy. I'd also like to be able to return to stock if I ever decide to sell. That's why the idea of simply disconnecting the antennas, as mentioned in #162, is appealing.

 

I am OK with the stock unit and the mic. I would like to keep them. But I do not want the DCM.

 

Cause the thread title was meant to be ironic…. kidding, but it seems like it sorta turned out that way

If I were more comfortable re-wiring and had not already gotten tired of taking stuff apart, i would take your approach. Sony makes a nice simple head unit, quick wireless and everything works.

I’m keeping the DCM for now, to avoid rewiring the speakers, but i have melted off the SIM from the pcb, removed the DCM battery, pulled the DCM fuse, and connected the resistors with the shortest interconnect FAKRAs. I had foil, but i didn’t bother re-wrapping the DCM the second time putting the DCM back in.

 

Would you like the donate your old DCM to @jboudreaux1965 ? He is looking into some more detailed exploration of this magic box.

 

oh you can just pull the whole thing out and the truck will run? Well shit, then I’m doing that! I don’t care about keeping it factory, or OEM, I just don’t want my truck constantly recording everything I do then tattling to Toyota. I also hate the fact that one day they or someone else could just decide to shut my truck off remotely, or hack it for fun. I’ll pull the DCM and replace head unit. Any model of Sony you recommend?

 

i am running the 6000 prewired from Trailgrid pro. They also include this bit of plastic l, as shown in their youtube youtu.be/X5_02EtAWko?. to help you mount the mic.
https://trailgridpro.com/products/sony-xav-ax6000-plug-play-bundle-16-22-tacoma

while you have the DCM pulling job going is a good opportunity to run the mic wire via the passenger side, since you will have the glove compartment, etc. out to pull the DCM.

 

I do wonder after going to all this trouble to remove the DCM, whether Russia, PRC, or Iran or whatever, hacking Toyota and then using Toyota’s systems to mess with or disable a gen3 Taco via the DCM cellular connection is even possible, or if it doesn’t really have the capability to even theoretically be used to get the truck attacked/hacked from a bad outside actor, or even a malicious inside Toyota power user.

Perhaps next to impossible to determine for certain without way more time than this thread has taken among everyone’s efforts, or an answer from a Toyota computer development person.

 

oh it’s possible, in the states there’s been a few stories of people getting their vehicles hacked while driving and some stranger making them crash, fatally I think a few times. Also a story about police remotely disabling a vehicle that was stolen using that same method. Which good in that moment, could obviously be abused.
Google provides lots of stories about these advanced electronic vehicles being susceptible to hacking and being made to crash or just shut down. If you completely remove the DCM and head unit it wouldn’t be possible because the door hasn’t been locked, it’s been bricked up and doesn’t exist anymore lol

 

I went with the TrailPro 6000 Sony head unit. Yes, I agree, the absolute best place for the DCM is on your coffee table. It appears to be "duct taped" onto the Tacoma. Other manufacturers systems seem to be more deeply integrated with the vehicle making removal impossible. On the Tacoma, simply remove it and disconnect its battery. Rewire the speakers and mic or get a new head unit. Done.

 

One reason i told myself I wouldn’t get a non-clutched or non-manual transmission Toyota is at least i still have the clutch and hand brake, which are hydraulic or cable controlled, and non-computerized or electronically assisted controls afaik, …. just based on fear of maybe unlikely freak accidents. Remember these stories? https://abcnews.go.com/Blotter/toyo...dly-unintended-acceleration/story?id=22972214

sure you could try to jam an automatic transmission into park, but i don't know if it would work or listen, and i am guessing the tranny would likely be totally wrecked if it worked. Even happened to that unlucky rich New York couple in the Niagara Falls Canadian border Bentley crash.

i think for sure Teslas have an open door to be disabled or messed with remotely perhaps more vulnerably than any other vehicle, maybe John Deere is nearly as controlling, but i think the amount of plausible control over a vehicle via the internet varies widely across vehicle makes and models, I’m not sure if every DCM is a real vulnerability to the rest of the vehicles controls, as opposed to informational exchange only, still glad it’s been disabled, just in case, since I wouldn’t trust Toyota’s official answer, maybe some day, during the future great mass bricking or cyberattack on America’s personally owned vehicles crisis, I will rejoice that my truck is still operable and will rewire the speakers and pull the dcm entirely, but i doubt it will be something i make time for even though there’s some nice rca connectors with caps already dangling off the back of the head unit.

 

Is anyone running 35's? Just wondering if when you log in to your account and your mileage is automatically updated, is it reporting the miles on your odometer OR are the miles being tracked and reported by GPS? It would make since from the manufacturers point of view. With 35's for every 100 miles on the clock I really drove 114 miles. So every 1000 miles that's an extra 140 miles free warranty. Every 10,000 miles that's an extra free 1,400 miles of warranty, etc...

No one can explain this to me...

I bought the truck new it had a couple miles on it. I ordered my new 3rd member from ECGS, in the mean time waiting on it I drove at least 300 miles.

I set my trip odometer when I changed the 3rd member to keep track of the miles to change the oil in it.

When I pulled all of the OEM stuff out, head unit, wires DCM, all of it, something weird happen to my odometer. Look at the pics.

My trip odometer from when I installed my 3rd member has MORE miles logged than the odometer on the truck???

 

Hmmm, wondered about this too, but assumed odometer would be based on the wheels turning only, and never posted or searched for answers…. If this comes up much, i would think there would be more posts around the internet about warranty / mileage issues.

What’s a “3rd member” in the context of your post?

 

I regeared it, I took the 3.73 gears out and put 4.56's in it

But I didn't recalibrate the speedometer, so it still thinks it has 30" tires. 1 rotation of a 35" tire is covers about 14% more distance than a 30" tire. All 3 of my GPS speedometers, head unit, ScanGauge 3 and phone said I traveled approx 116 miles on I-10. The odometer reading about 102. I'm wondering if I had a DCM when it reported home which number would it send?

Anyone with bigger tires notice if their odometer miles are different than the reported miles that get uploaded?

 

I didn't take pics of the unit while it was still in the truck. Before I start sending voltage to the board for testing does anyone have good pics of the board connected to the plug showing which color wires connect to which pins on the plug or better, the board? Or even some good pics of the plug and wires on the truck could help me out.

Also, are we sure the board is only getting 12v power? There isn't any sort of step down on the power source is there?
the next time someone has everything taken apart and can access the plug on the truck, can someone put a meter on the plug and test to make sure that 12 volts are being fed to the board.

Thanks guys!

 

The schematic has the wire colors noted for each wire to the connector; I've found it to be accurate too. The only wires that are not called out on the schematic are the two CAN wires.

See attached for Toyota's color code, page 3.

The power regulation to lower voltages than the vehicle supply (~12VDC) is accomplished within the DCM by a yet unidentified chip(s). The relay coil that controls the speaker routing is powered by 3VDC for example. So that is one of the voltages the internal chips of the DCM use. I would suspect 5V as well and some circuit with a higher voltage than the battery has to charge that internal battery. I've not identified any chips except the SIM.

In my design days we would have used the easy to use and understand Three-terminal regulators; I saw no indication of those on the DCM board.