Simpler solution for disabling the DCM telematics - Silencing Antennas

Pretty sure it’s independent. I already swapped the head unit myself. But, maybe not if you have a 2017, not sure which was the first year it connected to the internet, so may or may not apply to you.

 

The DCM module is an entirely separate module from the aftermarket head unit. It shares some wiring connections to the speakers, microphone, and CANBUS as the headunit, but it is it's own module located off to the far right corner behind your dash as seen in this diagram from doc RM100000001L098:

 

edit 2/1/2024: I was able to fix the issue by wrapping the DCM module in aluminum foil

I suspect my truck is still somehow communicating back to mothership Toyota after performing the mod. A few days ago I installed a remote start system that requires the interruption of a TPMS check. I received a voicemail from the stealership today about bringing my truck by to get my tire pressure looked at because my TPMS light was on... That prompted me to sign into my Toyota account and surprisingly my current mileage is accurate and I had a green checkmark saying "data is transmitting" but the fuel level is wrong and the last updated date has no data since it defaulted to the beginning of unix epoch time. There was also vehicle alerts every day I used remote start since I installed it I presume due to the TPMS issue but unfortunately details about the alerts are non-existent. I realize I could unenroll from "Service Connect" so I stop getting called but for now it will be a good test if my truck is still communicating.

I uninstalled the Toyota app. Maybe the truck can send limited information like mileage and engine codes through a connected phone.

Perhaps there is some truth about using short adapters to prevent the wires functioning as a short antenna. I might order the short adapters and give that a shot.

I drive right by a new Toyota dealership every day going to and from work. Could Toyota somehow communicate over a non-cellular short range wireless system based out of dealerships?

Anyone know of other antenna connections in the truck that could be terminated in a similar way?

I spitballed a few ideas and I'm open to others. I will post again if I learn anything new.

 

Acckkk, discouraging that the mod might not be 100% working.

Do you have an oem or aftermarket head unit?

How do you connect your phone (via carplay usb, etc.), is there any possibility it might share its internet connection via android auto or carplay?

would wrapping the cables in foil all around stop signal transmission leakage, acting as faraday cage effectively? If not how can leakage be stopped?

i’m surprised it picks up on the tpms thing so fast, or that that had anything to do with remote start.

Btw, When i tried to opt out by pushing the phone button, the phone rep basically said i would need to opt-in install the Toyota app, and enroll first, then request to opt out later. I have never had the Toyota app setup.

 

I have an aftermarket Pioneer DMH-2660NEX. I connect my phone with bluetooth only for hands free calling. I don't think the headunit has wireless carplay and I don't plug my phone into the headunit. The TPMS was strange for remote start but seems to be working as intended. I saw the option to disable "Service Connect" in the application but I would like to disable everything from my side instead. I'll see if it continues communicating over the next few days after uninstalling the app, but I will probably be trying the shorter adapters. Hopefully I don't have to wrap the DCM module in aluminum foil.

 

Damn, that's frustrating. I don't think there' any (documented) additional antennas that Toyota stuck in the DCM module, but I did find that after a day of dirt road driving one of my SMA terminator caps did loosen up and started transmitting. A quick re-tighten with a pair of wrenches and that was fixed.

I'll also try one of those shorter connectors just in case it's possible the whip isn't actually a fully-shielded coax.

 

I'll try tightening the SMA terminator caps a bit tomorrow and see how that goes.

 

Id bet thats the issue

 

So hopefully I'll be putting these in soon, but in case not, or this is useful to see, this is how big the interseries connectors look with the Amphenol 132360 resistors. The metal part spins inside the plastic part of the fakra by the way. All the fakras were made in prc and there's no easy to tell difference other than the higher price and fancier packaging that the proxicast brand came in.

 

Some things I have learned

Toyota's website and app suck. I would get different results displayed for mileage and vehicle health history looking at the Toyota website on my phone vs desktop. I did figure out refreshing the page is not enough, you must click refresh next to last updated in the Vehicle Health Report to update the current mileage. After I figured out how to update the current mileage I was able to use it as an indicator of my truck communicating with hivemind Toyota. Even with the mod installed and a red SOS light within an hour of turning the truck off the mileage would update on the Toyota website.

Removing the Toyota app from my phone made no difference and the mileage continued to be updated.

I checked the tightness of the resistor connections. One of the resistors was not a tight as the others but I would not have described it as loose. I tightened the connections more than they already where but the truck continued to communicate and update the mileage.

So I tried the short adapters without the wires (

RedYutou FAKRA SMB Z Type Female to SMA Female Connector Adapter for GPS Navigation Coax Cables (2 Pack)

https://www.amazon.com/dp/B0CHBKL39H?ref=ppx_yo2ov_dt_b_product_details&th=1). I really liked the tight fit of this install, but this still allowed for communication and the mileage was again updated on Toyota.com.



One thing I found strange was receiving an email from "Toyota Privacy Team" two weeks after performing the antenna mod about a request submitted to "Not Sell or Share My Personal Information". You can make these privacy requests though the Toyota website. The email was worded as if I had submitted the request. I did not submit a request. I have included a photo of the email below with personal details removed. Even though I did not submit the request all of the information was correct. Why would someone at Toyota do that without my asking? Perhaps the truck can only transmit limited data with is not as useful to be sold or shared? Maybe Toyota got tired of seeing the TPMS sensor error my remote start system causes? I have submitted a request to "Get My Personal Information" just to see what's there, but that can take up to 45 days so I got some waiting to do.



At this point I am a bit stumped. I might terminate any similar antenna connections with resistors if I find them. I might even try wrapping things in foil... Wonder what the neighbors would think if they saw me doing that?

 

Any chance the home Wi-Fi is linking to the truck?

My 21 has wifi, but I don't use it or know if it's functioning.

 

(Exactly what I thought too. My '22 has the Wifi and is linked to our home network.)

And as much as I like the idea of blocking Toyota or anyone from tracking me - I also REALLY like being able to see on my phone where my truck is. So for now the antennas stay.

 

I never set up anything wifi related on the stock head unit and the current mileage updates regardless of where I park my truck be it home, work, or the store far away for any of my wifi networks. At this point I'm assuming there is a redundant cellular communication system somewhere in the truck. Just to be thorough I will log into my home wifi router and look at the connected devices in case maybe I set up wifi and don't remember it.

 

You can do that with airtags, tiles, or a backup cell phone that's not part of the truck.
Since it's not an EV and doesn't support remote start or climate settings I don't see why the Tacoma should be on the Internet.

 

There has to be some write up somewhere as to how this DCM works. I somewhat recall there was a way the dealer/manufacturer could download without cellular in their service bays - could be wrong.

Since these FAKRA connectors are not Toyota, could it be that they are not making connection to the center pin? Thus not terminating the signal.

 

What years is this “mod” for, the ones wirh the TSS?
I don’t think my 17 has any of that nanny stuff.

 

I wish I knew about this, I ended up buying a blue sea switch.

Was that pic you’re setup, where’s the in/out button?

Warn did fix the wireless remote design and I need to install the kit.

 

So to be clear this is only if you have an SOS button, correct? My 2019 doesn't have any of that and AFAIK has never updated itself. I have to run TIS and load the cuw files myself then retune w/vft software.

 

Some additional info I found:
Cab Antennas.pdf

Will PM you later when I take a picture in the daylight and to take this topic off this thread.

 

My assumption is that unplugging the antenna or having the connector not make proper contact would result in a check engine light, but I have not tested that assumption.

As far as I can tell the SOS button/cellular functionality was added to 2020 Tacomas so I think both of you are fine.

Thank you for that PDF. It is a good starting point for where I should be looking.