how to disable the DCM/Telematics unit in the car

Hmm, battery issues related to the DCM seem to be virtually an urban legend. I don’t think I have had any.

Without the DCM, navigation, traffic information, TJA on the Gen 5 PHEV, and SOS would not work among other things. I would keep it functional. I’ve also found out that the traffic information works even without an active Toyota Connect subscription, which is great.

 

You guys are still so weird for trying to dissuade people from disabling theirs. What does it matter to you? Seriously. Why do you care to try to talk anyone out of it? It doesn't hurt the car. It increases security and privacy by disabling it (and no one cares about your likely retort that we're all being tracked by our phones, we know, but with a simple pull of a fuse we can not be tracked by our car company and not lose a single feature that isn't already easily handled by the phone).

Oh and who the hell would use the traffic information when we all have carplay and android auto and waze? Weird behavior. Weird reason to even keep the DCM powered up. Having the in-car microphone working is a more compelling reason than toyota traffic info. Only some weird NPC type person would be like "hey honey, let's not use waze, google maps, or apple maps, let's check the toyota traffic information system ".

Also please read through the thread, I've posted many links to articles regarding issues with DCMs through car manufacturers. It's not an urban legend. Subaru even went as far as making a dongle to bridge connections to restore mic and speaker functionality in theirs after they had to do a recall for issues when 3G shut down. The DCM is a massive liability in all regards. It's a security liability, it's a privacy liability, and it's a reliability liability. And you add these liabilities for what? Toyota traffic info and an SOS button? lol gtfo

 

LOL I am not trying to persuade you to do or not do anything. Do or not do whatever you want. I am telling you that I am not disabling my DCM for the reasons I explained.

 

Priipriii suggests trying # 16. If you do, let us know if it works.

 

Greetings, my friend. I see you're on the right path. I chose to unsolder the esim from the module. The data grab definitely occurs even without antennas/battery connected to the module, saw it with my eyes. Microphone and speaker works in my case. I also get traffic data even though I'm not sure where it gets that. But removing the sim disabled the sos button and toyota app connectivity.

 

So basically what I did is disassembled the transceiver/telematics block, so that you only have the
microboard circuit part of it. Then opened up the Kyocera Corporation's modem and removed the chip for eSim receival by Verizon. You have a different Prius. If you'd shown the telematics block to me, I would try give a look.

 

Seems like a lot of work to go thru

 

Is it? The hardest part is to move the screen out of the way. If you don’t have the soldering station you can delegate the process to someone else for like 20 bucks

 

While removing the DCM SIM should stop data transmission, it would still permit the logging of the data to the DCM's onboard memory, which can later be downloaded. While removing the SIM retains the cabin microphone and speaker function, it's both non-reversible and insufficient for my purposes.

Pulling the 5A fuse indicated in the attached diagram and waiting for the DCM internal battery to discharge *appears* to disable the DCM. All DCM features are disabled, including the SOS button. Everything I use continues to work as advertised, with the sole exception of the interior cabin microphone. You know when the DCM internal battery has discharged, because the cabin mic stops working.

However, because I never activated any of the data functions, installed the Toyota app, or agreed to any of the Toyota data terms, I have no way of determining if, with this fuse pulled, all functions of the DCM are truly disabled or that all transmissions have stopped. On the other hand, the car is not displaying any error messages. Yes, I know the TPMS modules also transmit, but I'm not concerned about tracking, only vehicle data.

The only way to be sure the DCM is fully nonfunctional, and no part of it is still being powered by another circuit, would be to fully unplug all DCM connectors. If the DCM is fully unplugged, it's well reported that, in addition to the cabin mic needing power, there are a couple speaker wires which need to be jumpered with two short lengths of #22 solid core wire.

1) Is anyone willing and able to send me the disassembly instructions to non-destructively get to and unplug or remove the DCM on the Gen5 Prius?

2) Rumor has it from other Toyota owner forums that the mic only needs a 5v supply to function without the DCM. Has any Gen5 Prius owner succeeded in restoring the cabin mic after disabling the DCM? If so how? Does anyone have the cabin wiring diagrams for the Gen5 Prius or Prius Prime?

 

You flatter yourself thinking anyone in Japan, (or wherever it is that this 'tracking data' is sent to), is "Following you"...
Who exactly cares what grocery store or gas station you go to? How is it possibly a "Massive Liability"?

I'll tell you who cares what grocery store or gas station you got to. Google. But you seem fine with that and "Don't care".

I guess it's harmless to have this level of paranoia directed at your stupid car. It could be worse... Carry on!!

 

Not to mention that you are unkindly mutilating the car for the next owner (this is exactly why I don’t buy used cars anymore) and telematics will be a legal requirement soon as the cars will have speed-limit-exceed warnings.

 

That will be for new cars only after a specific date and won't affect used/old cars