Seems from this older Tundra Forum thread that the DCM functioning correctly is required to use the key fob to start. Though the consent to use Connected Data services to use the fob remote start seems to have been discontinued.
I am confident that your vehicle is constantly/ regularly transmitting data to Toyota no matter what you do, unless you disable it yourself.
I disabled my DCM, so this isn't an issue for me.
I suspect you somewhat misunderstand the situation.
AHH bypass only partially worked for me. 2025 Camry hybrid awd. Speaker ok. BT microphone shows no response on back screen. They sent me a new harness. Reinstall scheduled for September 10. I'm thinking if that fails an alternative method would be to plug in 50 ohm terminators to each of the three antenna leads. that should cause the DCM to behave as though the car is in a dead zone(no 4g or 5g detected). Unfortunately that would consume a little more battery power. So for cars parked a long time that could be a problem. Then of course there's the problem of finding a properly fitting 50 ohm Terminator for each of those 3 sockets.
BT mic failed for me too.
Right. That is expected. I had https://www.compustar.com/remotes/pro-2wg18-no-lte/ installed. It will be good for warming up the car in the winter. But it's kind of a nuisance because as soon as you open the door the car turns off. (I think)That's because the switch over would require a working telematics unit that talks to Toyota. But it has good range two football fields at least. I think it works via spread spectrum FM frequencies.
So your Bluetooth speaker worked fine? That's good I was looking for full working confirmation from someone with a 2025 model. Maybe I just got a bad harness. Or maybe my mechanic did something wrong on the install.
I have zero issues. The DCM itself is "dead" as it has zero connection to power or communication with the ECU.
Posting a how-to on grounding out the antennas used by the DCM telematics module.
This post is not a debate about the puposes of telematics communicating data back to a toyota service center ,or legality of same -- only a how-to for those interested.
Background - why bother?
- All recent toyotas have a always-on cellular connection to Toyota corporate via thee internet. This enables lots of data reporting and remote monitoring & control of the vehicle. This includes GPS location, speed and other data. Maybe you don't care, maybe you feel the pros of being connected outweight the cons; but some people don't want this data being sent at all.
What data gets sent?
I Refer you to the 2024 service manual where it says:
The HOW-TO for those interested:
I know that on other Toyota models, pulling the DCM fuse results in a Check Engine Light. I Haven't tested this on my Taco; but i don't want a bogus CEL masking other legit causes for CEL. So i looked for a method to keep DCM communicating to ECU but not the outside world.
After some research I found this thread. This method takes less than 15 minutes and is completely reversable. Basically unplugging three oem cables and plugging in three terminated dummy cables which tell the DCM it's out of range for cellular and GPS. This does NOT affect any other cellular or GPS devices you might have in the vehicle.
First, I looked up the location of the DCM module in my 2025 Taco. It's behind the phone shelf/charging area just ahead of the shifter.
I purchased three 'Fakra Z Female to SMA Female Vehicle Antenna Adapter cables' and some 50-ohm SMA terminators off Amazon. The square Fakra Z shells on the jumper cables need to be removed leaving just the inner coax connector, becuase the Fakra shells are are too Fakrin' wide to fit into the Toyota DCM. Do this carefully so as not to damage or bend the inner coax connector fins.
Accessing the DCM is easy; the panel holding the phone shelf/Qi charger basially pops forward and unclips. Once loose it can be pivoted to the right allowing acess to guts of the console. The DCM is front and center.
The antenna leads are on the left:
The latches for the connectors are at the front. I suggest using a right-angle tool such as a pick to push the latches inwards while tugging gently on the cables. They pop out easily.
Install the terminated jumpers into the three DCM sockets you just freed up. The connectors have a slight interference fit so they won't easily fall out.
You could probably? just let the jumpers dangle in the dash area but i wanted to take their weight off the interference-fit coax connectors at the DCM side. So I used an ahdesive-backed zip-tie mount and a zip tie stuck right to the front of the DCM, through wich i looped the three new jumper cables. Now there is no weight pulling down on the connectors landed in the DCM.
I Pushed the three OEM cables back into the dash and let them dangle.
I started the truck at this point to check for any CELs... no problems found.
Reinstall the phone shelf/carger plate in reverse sequence. Start the bottom with the vertical fin connectors.
That's all there is to it. At this point the DCM will this it is out of range for both cellular and GPS.
Note: the OEM "emergency assistance"button and other "connected services" are now diabled, obvi, as it requres that built-in cellular link. I infer that pulling the onboard GPS antenna also functionally blinds the onboard oem navigation. If you use onboard oem Nav, the you could experiment with reconnecting the GPS antenna only I guess? YMMV.
This will NOT affect any carplay, cellular or GPS accessed via a paired smartphone.
Posting a how-to on grounding out the antennas used by the DCM telematics module.
This post is not a debate about the puposes of telematics communicating data back to a toyota service center ,or legality of same -- only a how-to for those interested.
Background - why bother?
- All recent toyotas have a always-on cellular connection to Toyota corporate via thee internet. This enables lots of data reporting and remote monitoring & control of the vehicle. This includes GPS location, speed and other data. Maybe you don't care, maybe you feel the pros of being connected outweight the cons; but some people don't want this data being sent at all.
What data gets sent?
I Refer you to the 2024 service manual where it says:
The HOW-TO for those interested:
I know that on other Toyota models, pulling the DCM fuse results in a Check Engine Light. I Haven't tested this on my Taco; but i don't want a bogus CEL masking other legit causes for CEL. So i looked for a method to keep DCM communicating to ECU but not the outside world.
After some research I found this thread. This method takes less than 15 minutes and is completely reversable. Basically unplugging three oem cables and plugging in three terminated dummy cables which tell the DCM it's out of range for cellular and GPS. This does NOT affect any other cellular or GPS devices you might have in the vehicle.
First, I looked up the location of the DCM module in my 2025 Taco. It's behind the phone shelf/charging area just ahead of the shifter.
I purchased three 'Fakra Z Female to SMA Female Vehicle Antenna Adapter cables' and some 50-ohm SMA terminators off Amazon. The square Fakra Z shells on the jumper cables need to be removed leaving just the inner coax connector, becuase the Fakra shells are are too Fakrin' wide to fit into the Toyota DCM. Do this carefully so as not to damage or bend the inner coax connector fins.
Accessing the DCM is easy; the panel holding the phone shelf/Qi charger basially pops forward and unclips. Once loose it can be pivoted to the right allowing acess to guts of the console. The DCM is front and center.
The antenna leads are on the left:
The latches for the connectors are at the front. I suggest using a right-angle tool such as a pick to push the latches inwards while tugging gently on the cables. They pop out easily.
Install the terminated jumpers into the three DCM sockets you just freed up. The connectors have a slight interference fit so they won't easily fall out.
You could probably? just let the jumpers dangle in the dash area but i wanted to take their weight off the interference-fit coax connectors at the DCM side. So I used an ahdesive-backed zip-tie mount and a zip tie stuck right to the front of the DCM, through wich i looped the three new jumper cables. Now there is no weight pulling down on the connectors landed in the DCM.
I Pushed the three OEM cables back into the dash and let them dangle.
I started the truck at this point to check for any CELs... no problems found.
Reinstall the phone shelf/carger plate in reverse sequence. Start the bottom with the vertical fin connectors.
That's all there is to it. At this point the DCM will this it is out of range for both cellular and GPS.
Note: the OEM "emergency assistance"button and other "connected services" are now diabled, obvi, as it requres that built-in cellular link. I infer that pulling the onboard GPS antenna also functionally blinds the onboard oem navigation. If you use onboard oem Nav, the you could experiment with reconnecting the GPS antenna only I guess? YMMV.
This will NOT affect any carplay, cellular or GPS accessed via a paired smartphone.
Fantastic info indeed, and this method does not need AHH bypass, so BT microphone and Rt Side front speaker will not get broke.
Given you have a Camry and are posting in a Tacoma forum, it is anyone's guess if yours works the same! But the antenna shorting method will kill the transmission of data, so it will work on any vehicle, if you can locate the DCM.
