Simpler solution for disabling the DCM telematics - Silencing Antennas

look for DW10a and LN5406. They provide lithium battery protection and outputs at 1.8, 3, and 5 volts

 

NEW REASON WHY YOU NEED TO REMOVE YOUR DCM (AKA BIG BROTHER TRACKER)

https://vimeo.com/978707294

I still think Toyota is tracking your mileage by GPS, not your odometer. I set my trip odometer when I put in my new gears to keep track of miles. Since I've removed the GPS tracker my trip odometer has more miles on it than my main odometer!

(I'm running 35's)

 

Does the key FOB remote start still work after the SIM removal?

I did the terminate to a 50ohm resistor trick last year, and always see a B15CB11 and B153711 (Antenna Circuit Short to Ground) under telematics in Techstream. No other indications of an issue. However I assume due to security protocols it disables the key FOB remote start with any telematics error set.


PS. I tried driving around without the antennas plugged in, but getting close to a cell tower was enough to pickup a bar or two of signal so it could phone home.

 

Do you have any of the Toyota App stuff active to confirm whether the DCM unit does indeed transmit/communicate to the Toyota server with those one or two bars of signal? The ability to receive a weak signal from a Cell Site Antenna without a designed antenna connected does not mean that the DCM would risk its life by trying a high power transmit without a suitable antenna connected. Possibly if an accident was detected a transmission could be tried by the DCM as that may be a life-or-death circumstance for the occupants, but regular vehicle conditions I would not think Toyota would consider to be important enough to destroy a DCM which the vehicle owner (after the expiration of the warranty) would have to foot the bill for. I'm giving Toyota a break on this one - not sure they deserve it though.



In my current configuration the "Remote Start by use of the FOB" works just fine to remotely start the vehicle.

Current Configuration at the DCM:

-SIM chip removed internally. - This is the biggest bang for the buck and disables the cellular completely - or so that is my thought.

-The three antennas unplugged from the DCM - - I don't believe this is necessary since the SIM chip is removed - just how I have it. Plus, I like seeing those errors in Techstream.

-The USB connection to the radio head unplugged (connection immediately below the three antenna coaxial connectors). This removes all the DCM indicators on the radio head. Like the ones you are seeing when you get close to a cell site.

-The speaker connector is still plugged in, and I have front right side speaker use. This works whether you power the DCM or not.

-Large multiconductor connector on the DCM is still plugged in - this leaves me with the use of the Bluetooth microphone since the microphone is powered by the DCM. This is also required for the "Remote Start by FOB"; just tried unplugging this connector and the Remote Start by FOB did not work. I had previously thought the TPMS receiver preformed this function.

Under hood fuse box still has the 10A DCM fuse installed supplying power to the DCM.


Side note:
Not yet addressed is if the DCM could communicate to the Toyota server via the Wi-Fi or the Bluetooth on the vehicle to the Toyota server when near a dealer with the cellular disabled.

 

It’s interesting that having the antennas unplugged shows a techstream error, but does not prevent remote start. I haven’t torn things back apart to remove the resistors and check remote behavior, but the short to ground are the only TS errors i see.

I don’t remember for certain now it’s been more than a year, but I thought I checked the app and saw something like mileage update with antennas unplugged.

Everything I read says a cell phone will connect to 911 even without a SIM. So I guess unplugging the antennas might not be needed since your network identity is gone, but technically it would still able to connect.

 

I understand if your phone cellular service provider (say AT&T) is not available in the area you are in, while a competitor (say Verizon) is, the phone can still make contact with 9-1-1 using the competitor's cell service. Haven't heard anything about this emergency 9-1-1 access without a SIM. There are lots of other numbers associated with the cell phones and cell service beyond the telephone number, so maybe it is possible. However, I doubt the DCM could still call the Toyota server and I think that is what happens in the case of the driver presses the SOS button or in the case of an accident. Don't recall reading anything about the truck calling 9-1-1 in the Toyota information supplied with the truck. But, like you that was some time ago in my memory.

 

Where is the telemetrics screen in Techstream?

 

Why not just remove the whole unit?

 

Any cell phone can make an emergency call on what's called the "USA Network"

(I used to be really big into programming cell phones "repairing ESN, MEID and IMEI's)

Even with the serial number erased and the phone not associated with any provider if you try to make a call you get a message from the USA Network saying you can make an emergency call.

 

See what you quoted:
-Large multiconductor connector on the DCM is still plugged in - this leaves me with the use of the Bluetooth microphone since the microphone is powered by the DCM. This is also required for the "Remote Start by FOB"; just tried unplugging this connector and the Remote Start by FOB did not work. I had previously thought the TPMS receiver performed this function. No extra wiring for the mic and I retain a feature not available otherwise.

To your other question regarding Techstream:
When you open and connect to the vehicle a large list of modules (30+) come up in the center screen. I do not recall just what it is called, but it is there.

 

Are you saying if I removed the SIM card from my iphone I could still call 9-1-1?

 

Just read through most of this thread. Thank you so much Toycoma2021 for all the documentation and apologies if this info is already available elsewhere, I tried searching for "dcm speaker" and this is the first thing that comes up. My question is, is there pictures/documentation anywhere showing specifically which pins to bridge on the dcm connector to get both the speaker and mic working with the plug disconnected from the dcm unit? I understand I could just leave that plug installed but I'd feel more comfortable just having the dcm completely disconnected and then just jumpering the plug since I'm comfortable with simple rewiring

 

That’s the way it works. The electronics are there for multiple scenarios.

 

I understand “comfort” levels well.

No, not in this thread will you find either the speaker connector jumper connections or the wiring of a 5VDC source to power the microphone. I’m on my phone and I suck at searching, but there are other, older threads addressing each of these issues. The speaker is real easy to add two jumpers to the 4-pin connector that plugs into the DCM. Perhaps the wiring diagrams attached to this thread would help you with that. Some have simply de-pinned the connector and wrapped wire around the respective 2 conductors (much like old fashioned “wire-wrap” connections) others have sourced appropriate size wires to insert into the female connector to make the connections.

As for getting the microphone working again. I’ll just say that as far as I can remember the 5VDC powering the Bluetooth microphone is normally generated by the DCM. There is also a 5VDC source at the radio head in the center dash. That is what I have heard others used.

Some have thought they found a 5VDC source at the large DCM connector and tried it to no avail, it turned out it was a logic level 5VDC and was incapable of supplying enough power to the microphone. iirc

If you are familiar with 3-Terminal regulators you may try a 7805 at the large DCM connector. After all there is 12VDC, ground and the conductor that goes to power the microphone already present. I had thought of using this tactic and sell the product, but the matching connector is not produced that I could find.

 

Next time I’m in the forest I’ll take an old SIM-less phone with me and try a 9-1-1 call.

 

Got it I'll look back through and find the wiring diagram, I can live without the mic. I'm somewhat familiar with voltage regulators but I may not even be hooking my phone up through Bluetooth anyways as I'm gonna wire in an aux port as soon as the harness I ordered comes in. Good to know the speaker fix is just a simple jumper, thank you for the help and again for taking the time to research all this. Most of the threads I found before this one were just people arguing about privacy

 

See bottom of post #166 for schematic.

 

Make sure to go where there is no signal… brilliance on display.

 

Brilliant assumption. Actually I picked the forest where I know where only one cell site is and just what jurisdiction the call will be answered and possibly the person on duty.

 

Disconnected the DCM last night, very easy thanks to all the resources here. Ended up jumpering the pins for the speaker with some 22 gauge solid core wire, worked perfectly