DCM / Telematics Module Bypass

[josiahg52]

I removed the fuse to the DCM. It's in the fuse block under the glove box. Center row of fuses, the last one in the line, closest to the motor. Easily done. I don't care about what it provides, but, I do care about who gets that information. Big brother knows to much already. After removal, I can't detect any difference in operation. If anybody else has done this and found a problem, please let me know. Wondering what the dealer will think at the next service.

Hmm. Thanks for posting this. A couple questions, because there seems to be a lot of conflicting information floating around regarding the DCM on the 6th-gen 4Runner.

When you say you "can't detect any difference in operation," what specifically have you tested? Some of the things I've seen reported or discussed include:

- Loss of microphone functionality (Bluetooth calls, voice commands, Siri/Google Assistant)
- Loss of a speaker channel (I've seen references to the front-right speaker on some Toyota platforms, but haven't necessarily found a confirmed 6th-gen 4Runner report)
- Loss of key-fob remote start
- Loss of app-based remote start and connected services, SOS functionality and telematics alerts
- Cellular/GPS status indicators in the infotainment system
- DTCs or faults that may only show up during dealer service
- Any affect on proximity unlock

The reason I'm asking is that the manufacturer of the DCM bypass harnesses specifically states that the DCM fuse must remain installed because it's needed for hands-free microphone functionality. That would seem to suggest that simply pulling the fuse could affect the microphone.

Have you had a chance to test any of the following?

-Bluetooth phone calls (can the other person hear you?)
- Voice commands / Siri / Google Assistant
- Key-fob remote start
- Balance/fader settings to verify every speaker is working
- Any warning messages or changes to the connectivity icon on the infotainment screen
- Whether the Toyota app still communicates with the vehicle at all, if you have an account and registered the vehicle.

I'm not particularly concerned about losing connected services, SOS, or app functionality. My main interest is understanding whether pulling the DCM fuse has any unintended side effects on vehicle functions that aren't obviously related to telematics.

So far your report is the first one I've seen from a 6th-gen owner who has simply pulled the fuse and reported no obvious changes, which makes it especially interesting given all the assumptions that seem to have carried over from other Toyota platforms.

Sponsored

 

[Snaker]

I just pulled the fuse and this is what I noticed:
1. You lose remote start via key fob (which sucks since I often use that feature to warm up my car during the winter)
2. Speakers remain unaffected. I tested all the speakers and they work as intended (I did it by focusing the sound on each corner of the vehicle)
3. There is the satellite icon that is grayed out with a slash though it (although I rejected all data collection via the app when I got the car so it has been like that ever since so I'm unsure whether pulling the DCM fuse might do the same thing for you)
4. I am unsure about whether all of the microphones work but I know that at least some of them work since I said "Hey Toyota" and it activated.

 

[josiahg52]

I just pulled the fuse and this is what I noticed:
1. You lose remote start via key fob (which sucks since I often use that feature to warm up my car during the winter)
2. Speakers remain unaffected. I tested all the speakers and they work as intended (I did it by focusing the sound on each corner of the vehicle)
3. There is the satellite icon that is grayed out with a slash though it (although I rejected all data collection via the app when I got the car so it has been like that ever since so I'm unsure whether pulling the DCM fuse might do the same thing for you)
4. I am unsure about whether all of the microphones work but I know that at least some of them work since I said "Hey Toyota" and it activated.

Very interesting. It seems, without substantial testing on various trims and certain options, pulling the fuseis at least as effective as the bypass harness is electrically. Of course, the backup battery has to go dead to be entirely nonfunctional, but who knows if the 4Runner DCM for sure has a battery. The no key fob remote start is relatively new to me as the common experience, not necessarily the 4Runner en masse, seems to remain functional on some 4Runners or Toyotas.

Interestingly, I assumed the Hey Toyota command woulf be related to the Connected Services and therefore the DCM.

 

[Nodak]

Interestingly, I assumed the Hey Toyota command woulf be related to the Connected Services and therefore the DCM.

i am guessing for responsiveness, its hard coded into the hardware. but software wise, once it takes over it offloads thru the dcm/app cellular or wifi to get results back since the toyota use's the cloud for results now instead of the 5th gen using a internal storage for mapping (hence the old days you had to pay to update the map data via usb stick)

i personally use a garmin 7in unit because im cheap an lazy to give up what i already paid for. plus i can make my own map routes for trips in basecamp and up load to my garmin. (i just recently did this and re-did my maps for my trip from ND to ATL and adjusted the ATL to ND. last trip i had some funky suggestions to route me thru the middle of st louis/kansas city instead of taking me around the city via north bypass)

my wife and son just use android auto mapping cause they dont usually use the other garmin units i give them to use.

 

[josiahg52]

i am guessing for responsiveness, its hard coded into the hardware. but software wise, once it takes over it offloads thru the dcm/app cellular or wifi to get results back since the toyota use's the cloud for results now instead of the 5th gen using a internal storage for mapping (hence the old days you had to pay to update the map data via usb stick)

i personally use a garmin 7in unit because im cheap an lazy to give up what i already paid for. plus i can make my own map routes for trips in basecamp and up load to my garmin. (i just recently did this and re-did my maps for my trip from ND to ATL and adjusted the ATL to ND. last trip i had some funky suggestions to route me thru the middle of st louis/kansas city instead of taking me around the city via north bypass)

my wife and son just use android auto mapping cause they dont usually use the other garmin units i give them to use.

I'm the same way. Active cloud routing, looking up realtime POI details, realtime map updates, realtime traffic and hazard avoidance, some of other the other things, fine, make it a paid service.. Basic offline/local based navigation, FM radio traffic and routing, ability to update maps, basic POI database, that shouldn't be a paid feature. I'll try Android Auto but will keep a Garmin 3597LMT with me.

 

[127.0.0.1]

if you bypass DCM does the clock remain accurate ? I fiddled with DCM on my rav4 and it made the clock drift due to the inability to get clock from GPS

 

[Nodak]

I'm the same way. Active cloud routing, looking up realtime POI details, realtime map updates, realtime traffic and hazard avoidance, some of other the other things, fine, make it a paid service.. Basic offline/local based navigation, FM radio traffic and routing, ability to update maps, basic POI database, that shouldn't be a paid feature. I'll try Android Auto but will keep a Garmin 3597LMT with me.

well i have the 1yr free trial plus i added the 2yr plan PIO. i prefer my garmin 86 drivesmart but the android auto is nice to have as you can get hotel pricing up along your route, just have to be careful as the distance sometimes is like 300-500 miles out sometimes.

same goes for gas station prices, i can get pretty close to real time pricing so i can plan fill ups along my route, which my garmin cant really do to the same degree as android auto does.

using garmin drive helps but i find AA works better and more up to date for things along the route. but route fine tuning in AA is lacking vs the garmin where i can plan every detail of the route i want to take.

AA has better real time updates of HWP cars sitting on the side of road (waze integration) and updates on construction zones (but the constant pop ups of "is the construction still there" is annoying)

garmin does better showing you further out which lane you need to be in (this is really important in big cities to give you more time to move over to the correct lane/exit). garmin will give my 2-3 mile warning vs AA giving me barely a mile out (and in atlanta that is not enough time during busy traffic time)

used in conjunction with garmin and AA, i get the best of both. personally i would never use toyota or any other built in nav apps. i always find better resources with 3rd party apps or devices.

but im grumpy old guy so i tend to stick to the old ways. heck it took forever to get of all my old map books.

Sponsored