[Bockage]

Hello everyone! I've got same issue and mic didn't work (Rav4 2019 w/manual SOS switch). Shorting 18-34 and 19-35 pins solved that. Now I have no message "no mic" and Bluetooth option is available now, I can connect new devices and play music via Bluetooth. But Mic doesn't works, callers can not hear me. In the Service Menu under the "Function Check-Microphone check" microphone doesn't pass the test (it does not work). It seems like signal was been amplified in the DCM (not sure about that). Has anyone solved that? Could you please help? I really get used to handsfree talking using car's audio.

Spoiler: Diagrams

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looks like the mic needs power too (MCVD-MACC). Your best bet is to figure out what voltage it takes and connect that to a pin that provides that voltage. If it uses 12v that should be easy, but if not you don’t want to fry the mic. Maybe take a multimeter to it while the dcu is connected.

 

[lagooha]

looks like the mic needs power too (MCVD-MACC). Your best bet is to figure out what voltage it takes and connect that to a pin that provides that voltage. If it uses 12v that should be easy, but if not you don’t want to fry the mic. Maybe take a multimeter to it while the dcu is connected.

Thanks! Yes, according to manual the voltage should be always 4-6V. Do you have the description of all the pins of my type of connector? It would help me a lot to find a pin to connect to MCVD.

 

[lagooha]

looks like the mic needs power too (MCVD-MACC). Your best bet is to figure out what voltage it takes and connect that to a pin that provides that voltage. If it uses 12v that should be easy, but if not you don’t want to fry the mic. Maybe take a multimeter to it while the dcu is connected.

I've found USBV in the plug next to F36, connected it with pin 33. No luck. Same situation - mic doesn't work... Any thoughts?

 

[Innovator1]

Apologies for bumping an old thread as my first post on the forum. Prospective 2022 Rav4 buyer, concerned with data privacy. Posts 55 and 57 about the 2022 not starting after DCM fuse removal seem a bit suspicious; both registered on the forum solely to post in the thread, never followed up on what you would think would be major issue (car not starting), then never replied again. Wouldn't be unusual for targeted misinformation to be posted to a public forum to scare people from learning an easy(ish) fix to prevent vehicle tracking.

It looks like the DCM part numbers are the same between 2019-2022. In Walkabout's excellent original post, part number for his 2019 is 86740-42040. The same 86740 part number is used on the 2022. It does appear to be superseded by 86740-0R020 on a number of parts sites; same part, different revision. Cursory research (search eBay for "Toyota 86740") seems to indicate that different revisions have been used across different model years/models, and newer revisions would be used for replacements of failed units; so they should be interchangeable across this entire Rav4 (and other models) generation.

Again, it seems implausible that pulling the fuse would completely lockout starting the vehicle, unless the change was made via software/firmware updates, at which point it should impact other model years and DCU revisions with the latest updates.

Any regular posters with a bit of post history on the forum with a 2022 able to confirm this theory by pulling the DCM fuse on your 2022, waiting long enough for the backup battery on the DCM to expire (or more bravely open up your dash and unplug the lithium backup battery), and see if it truly won't start? I'm sure I'm not the only one to find this thread, your contribution may help many

 

[Just me myself and i]

What I found out about the Data Communication Module (DCM) on my RAV4 is that even after you opt out of any cellular services such as Entune and the SOS feature your car continues to send information to Toyota via the built-in cellular connection. They claim that you "may" receive a discount on your insurance (if you enroll for monitored driving reporting) based on your driving habits, but chances are you will be penalized for driving like I do! Just another reason to drop off the radar screen. So I made it a priority to disable such communication.

Disclaimer: You will lose some convenience and safety features by doing this modification you assume all responsibility for any damages, legal liability, inconvenience or injury that may occur.

In summary I pulled the fuse on the DCM and removed the internal battery. Presumably the battery is there to power the unit if you crash and destroy your 12 volt battery and want to send an SOS.

You can probably avoid the work I did on my car by removing the DCM fuse (shown below) and waiting for the internal DCM battery to die, but I have not tested this approach. The battery is pretty big for a cell phone so it may take quite a while. Verify that DCM is offline by the DCM status shown in the last photo below. Also be wary of using bluetooth as I mention below.

The DCM unit is located behind the HVAC controls on the dash. I made the job way more complicated by removing the center console which was not needed. The HVAC controls pop out using the plastic trim tools that are needed for all modern cars, apparently.

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Pulling out the HVAC controls and other components. I took out the radio/screen which was not necessary.

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The HVAC controls knobs look like this.

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The DCM unit is the lower shiny rectangle. Find two hex bolts (10mm?) that hold the unit in. Remove the DCM and disconnect the wires and antenna.


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The DCM unit with the battery cover off. I removed the battery on my car and replaced the unit.

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Location of the DCM fuse in the footwell along with all the other colored fuses. It is well marked on the fuse box cover, I think it was 7.5 Amps. I took way more plastic off than was necessary (no manual used).

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Once things are put back together you will see this display showing that there is no cell connection indicated by the image of a cell phone with the diagonal line through it.

One caveat, if you use bluetooth to connect your phone to the car DCM will use your phone to connect to the mother ship and presumably send your data. I only use my iPhone cable to connect to the car which does not have this effect.

Caution! For anyone thinking of pulling the DCM fuse, know that when the DCM battery dies your DCM unit may be permanently ruined. I wish this information was provided in this discussion. The cost for a new DCM unit installed by the dealer is $1200. Think twice before pulling the fuse. Fatal flaw by Toyota and they won't cover the fix if it happens outside of the warranty. Toyota is aware of this design flaw and put out TSB011220, but they won't cover it outside of the warranty. I'm so disappointed in Toyota not standing behind their poor design I will not buy another one again.

 

[Gamma742]

Caution! For anyone thinking of pulling the DCM fuse, know that when the DCM battery dies your DCM unit may be permanently ruined. I wish this information was provided in this discussion. The cost for a new DCM unit installed by the dealer is $1200. Think twice before pulling the fuse. Fatal flaw by Toyota and they won't cover the fix if it happens outside of the warranty. Toyota is aware of this design flaw and put out TSB011220, but they won't cover it outside of the warranty. I'm so disappointed in Toyota not standing behind their poor design I will not buy another one again.

There are battery shops where you can get a similar battery and solder it in. No need to replace the unit over a battery