[CorollaVirus23]

I saw a post saying there's a fuse labeled "DCM" in the internal fuse box near the driver's seat that one can take out (on a 2022 Corolla hybrid). I've also found a post saying the fuse is labeled "DCM/Mayday" in the main fuse box under the hood (on a 2020 Corolla). In either case, I see it mentioned that it's a 7.5A fuse.

However, I don't see any fuses matching these descriptions in either location. Am I missing something or did they move it, re-label it, or combine the circuit with another fuse? Here's a picture of the lid of my fuse box under the hood:

According to one of the threads I linked above, in the 2020 Corolla, the DCM itself is located behind the head navigation unit in the center console. Can anyone confirm this is where it's still located in the 2023 model? I saw a video on dissembling the console on a recent Corolla (although the car seems older than the 2023 model based on the head unit's appearance) and I didn't see the DCM there. The video, however doesn't show that part of the console very well, so maybe I'm just not seeing it.

I'd like to avoid having to disassemble the console if I can just remove a fuse. I realize there's an internal battery in the DCM, but I'm content to just let it die on its own if I can remove it from the main battery.

Any help is appreciated. If anyone has access to the repair manual, that also could help a lot. Thanks.

 

[CorollaVirus23]

I forgot to mention that I have a non-hybrid model, if that matters.

 

[PJTruslow]

They do appear to have changed the fuse block. That i fuse panel you have has been reorganized compared to mine, and mine has the 7.5A fuse labeled DCM/MAYDAY below the EFI-MAIN no 3 fuse.
personally I don't quite get disabling the DCM system, but at any rate 2023 was a mid generation refresh so it's not too surprising that the fues panels got revised a bit. hopefully for your intentions, the fuse has just moved somewhere else.

 

[CorollaVirus23]

Thanks, PJTruslow, yeah I hope I don't have to go digging into the console or worse.

 

[CorollaVirus23]

According to the repair manual, the fuse is now located in the "power distribution box" (see the attached picture). The location of the DCM is still under the head unit as it was in older models. So it looks like there's no other option but to remove part of the dash.

I haven't found any photos or videos of the power distribution box, so I don't know how accessible the DCM fuse is, or if it's situated in a way that could require it being removed entirely to access the fuse.

For that reason, when I get the time, I'll probably just go for the DCM directly since the video I linked in the OP already shows how to gain access to that part of the console. I'm not seeing any reason to think the fuse is easier to access than the DCM itself now that it's been moved to the console's interior. I wonder if they moved the fuse specifically to make this more difficult.

 

[PJTruslow]

The side cover of the dash is held in by a couple clips. Takes only a moment to pop off.

 

[CorollaVirus23]

Thanks. Yeah, now I see the side panel is very easy to get off. The repair manual made it seem like you have to take off 3 other plastic components and the rubber door frame before being able to remove it. You don't.

Problem is I don't see any fuses there and I suspect I'll have to take out the box to find and access them. It's not very easy to get my hand in there. It's all very cramped so I instead have been working on getting to the DCM itself.

Removing the paneling was easy, but there's a black plastic piece that has some wires running through it in front of the DCM that took me a very long time to remove. The nuts that hold it in place were on very tightly and everything is so packed that I had to buy a ratchet with an adjustable head to leverage it out (like the one the guy used in the video I posted).

So I then disconnected two connectors to the DCM but have been unable to remove four remaining thick black wires (the four wires on the right side of this picture):

From the wiring diagram I have, I suspect three of those are antenna. I don't know what the other black wire is.

connector diagrams:

If I understand the wiring diagram correctly, the numbered terminals correspond to the numbered terminals of the connector diagrams. This suggests the power supply is through one or both of the connectors I disconnected. This still leaves a mystery as to what the other black wire is. As I only see three un-numbered connections in the diagram (the antenna). Confusingly, though, both connectors have labels that overlap (both have labels 1 through 4 in the diagrams), so maybe my reading of them is incorrect.

I'm going to try again tomorrow to force the black wires out. I haven't been able to determine if there's little clips that have to be pressed to remove them, but I don't think there are. The repair manual just says to disconnect the wires and doesn't give any particular instruction on doing so.

If I can't figure it out, maybe I'll just leave it as is and wait a few weeks. If I'm right in thinking the power is through one or both of the connectors I removed, the DCM will run out of battery on its own and I don't need to worry about removing the other wires.

 

[PJTruslow]

Yeah in the schematics, the letter is which connector, which will be specified on the sheet, and the number is the pin of the connector.
I got the 2 day TIS subscription and downloaded everything. $35 well spent. Over 1000 PDFs

 

[CorollaVirus23]

Ah, thanks, that makes sense.

Is there a way to know what letter corresponds to which connector, other than inferring it based on the number of terminals? In the pdf download, at the end of the document, there's like 10 different connector diagrams, but I don't see a key or legend indicating which is which (clearly not all of them are even being used here so I'm not sure why many of them are shown in the pdf at all).

Anyhow, it looks like "A" in the wiring diagram must be the larger 34-pin connector that I removed. And it looks like that supplies the power from the 10A fuse. So hopefully that means I'm done.

That leaves a "B" and "C" connector. Maybe one of those refers to one of the black wires I can't remove. And the other 3 are the antenna, that would explain everything.

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I also bought a 2 day subscription and I wrote a script to help me save and name the pdfs. I downloaded just over 5,000 although I lost steam and didn't download all the connector diagrams.

They do a good job of making their web interface very annoying and difficult to use. Even though I wrote a script to help me, the entire thing was very labor intensive because their excessive use of javascript makes it difficult to scrape and I didn't feel like reverse engineering it to further automate my scraping. I'm sure this was all intentional on their part. But it didn't stop me from spending countless hours to save it all anyway. So I guess that means Toyota and I both lose.

 

[CorollaVirus23]

Right, so "C" in the diagram refers to the black wire, which is a three pin connector. And according to the wire diagram, that means it conveys USB information.

Turns out there is a legend on the wiring diagram (in the "Telephone Transceiver Assembly" block): "I143(A),I144(B),t7(C)". I143 is the 34-pin connector ("A" connector), I144 the "B" connector and so on.

So this all makes sense now and unless the DCM can also take power from the USB "C" connector ("t7"), I should be all set.

 

[CorollaVirus23]

I went out and tried again and managed to get the black t7 connector out. Based on the diagram I found, you have to push on the underside of the connector that's facing the ground. It wasn't easy, but knowing to press up on the underside did the trick.

I still wasn't able to disconnect what I believe are the 3 antenna, but at this point there's little point in bothering.

 

[PJTruslow]

I also bought a 2 day subscription and I wrote a script to help me save and name the pdfs. I downloaded just over 5,000 although I lost steam and didn't download all the connector diagrams.

would you share that script with me? I did it relatively manually, but found a way to make firefox print screen with no dialog, and automatically name the file according to the webpage name, but it did require me navigating to the desired page and at least pressing ctrl+P. I might at some point buy another subscription to grab any updated docs for the corolla, as well as a few other toyotas, since in my family we have a 01 Sequoia, a '10Tundra, a 09 4Runner, 2014 4runner , a 04 Tacoma, a 21 highlander, 22 Rav4, 05 camry, and a 21 Corolla. you could say my family has a VERY strong bias towards Toyota

 

[CorollaVirus23]

I don't think my method is any more automated than yours and it could be worse. But if it still sounds like it'd be useful, I'm happy to clean it up a little and post it. Let me describe it.

My python script calls the linux command xdotool which can simulate mouse movements, clicks, and key presses. For the repair manual, I used the same script for everything, but for the wiring diagrams I had to use two different scripts. Here's the workflow I used for the repair manual:

-I manually click on a page from the left hand side tree view.
-The script polls the mouse and waits for me to click the left mouse button, after detecting a click it waits a second then proceeds:
-By simulating a "ctrl + f" key press to find and then copy the Doc ID string
-It then does another "ctrl + f" to find and copy the page title
-It combines the two into a file name like: "RM10000000289TL SUPPLEMENTAL RESTRAINT SYSTEMS- AIRBAG SYSTEM- B003813 Second Row Right Side Airbag Deployment Control Circuit Open.pdf"
-It then simulates moving the mouse to the print button and left clicking it (I found that doing ctrl + p, resulted in pdfs that had text cut off, so I instead had to rely on pressing the print button shown on the web page to get good outputs)
-The script then presses tab twice & then enter, which on my OS and version of firefox, selects the file path dialog.
-The script then types in the file name and presses enter.

Then it goes back to polling for more mouse clicks.

If I need to left click on something without the script doing the above sequence, I alt + tab into the command prompt and press ctrl + z to temporarily stop the script. This is what I do when I need to expand or collapse the folders in the tree view. Then I resume the script by pressing "fg" in the command prompt.

I had a variant of the script that also auto clicked on the next page instead of waiting for me to do it. So in that setup I just moved the mouse to the next link and it'd click on it once it finished with the sequence of steps I described above, but this resulted in a lot of issues and I found it easier to just click manually.

Anyway, as you can see it's a very jerry-rigged solution, requiring you to initially set the cursor pixel position in the script for the print button, and to make sure the exact sequences of key presses (particularly in the print dialog) works for your version of firefox and your OS.

-------

This Corolla is my family's first Toyota. I'm hoping it lives up to Toyota's reputation of reliability that I keep seeing people talk about. Although I've also heard people say their golden era was the 90s, so hopefully I'm not getting in after their peak. I'm very tired of my vehicles falling apart so quickly!

One reason I chose the Corolla is also because it's so popular (most popular model of car sold of all time, ever). And I find that type of thing can be helpful because you can find more people online that have had a particular problem and posted about it.

That's partly why I use Ubuntu for my distro. Not that it's especially good; it just saves a lot of time because I can easily find solutions to many problems because there's a stackoverflow thread for almost everything. Not so with other more obscure distros.

 

[PJTruslow]

That's partly why I use Ubuntu for my distro. Not that it's especially good; it just saves a lot of time because I can easily find solutions to many problems because there's a stackoverflow thread for almost everything. Not so with other more obscure distros.

I use Windows 10 at home, but for work I do use Ubuntu. I do embedded and FPGA development. Embedded work is much easier on Linux, and Ubuntu LTS is the only linux distro supported by Xilinx tools and I don't have time to create issues for myself.

 

[CorollaVirus23]

I've created a video showing the process of gaining access to and removing the wires from the DCM. Maybe this will be useful now or in the future to someone:

Disabling DCM and telemetry in a 2023 Toyota Corolla LE

I show how to disable the Digital Communication Module (DCM) and the microphone in a 2023 Toyota Corolla LE. The DCM automatically sends location and sensor information to Toyota over the cellular network, which Toyota then sells to insurance compan…

www.bitchute.com

I'm unable (unwilling) to upload to Youtube right now due to difficulty in creating an account. But I welcome anyone to re-upload the video to Youtube or anywhere else because more people may be able to find it there.

The video I uploaded was actually in 4K, but bitchute converted it to an ultra-low resolution, making the wiring diagram I included in it unreadable. If you wish to re-upload the video, feel free to contact me and I can send you the 4K video. Or if you're reading this further in the the future and I'm no longer checking these forums, then consider linking back to this thread which has the full resolution diagram in one of the earlier posts in this thread. That or consider just re-posting and linking to the diagram as well. It could be useful if someone wants to avoid losing the right speaker and the microphone.