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.
View attachment 150083
Pulling out the HVAC controls and other components. I took out the radio/screen which was not necessary.
View attachment 150082
The HVAC controls knobs look like this.
View attachment 150086
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.
View attachment 150087
The DCM unit with the battery cover off. I removed the battery on my car and replaced the unit.
View attachment 150089
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).
View attachment 150090
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.