# I'm Building my own model 3 from scratch.



## Riley (6 mo ago)

I'm building my own model 3 from scratch and need help. I'm having trouble getting the vc modules to talk to one another.i am also having an issue where no audio will play. whenever I hit play nothing happens. if anyone knows a lot about the model 3 electrical system id love to get your help.


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## garsh (Apr 4, 2016)

Umm.... from scratch?


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## Riley (6 mo ago)

garsh said:


> Umm.... from scratch?


I’m buying each part of the car on eBay for as cheap as possible and wiring it all together. I have all the wiring diagrams and everything but even the official tesla wiring is kinda inconsistent. I might end up buying the wiring harnesses. But for the basic wiring I should be able to do it myself for now.


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## JasonF (Oct 26, 2018)

If you're going to do that kind of a project, you're going to need some kind of device to read and translate CANbus data, or you will go crazy trying to troubleshoot communication issues.


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## Riley (6 mo ago)

JasonF said:


> If you're going to do that kind of a project, you're going to need some kind of device to read and translate CANbus data, or you will go crazy trying to troubleshoot communication issues.


I was hoping I could just wire all the CAN the correct way and it would work but when I do nothing changes on screen. I expect to start seeing errors when the vc modules are working. Do the modules need to be reprogrammed to start working since they all came from different cars? If so I know they can be reprogrammed in toolbox 3 but I can afford that. I’ve read they will reset if you do a software update on the car but I don’t know if that’s true or not.


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## Madmolecule (Oct 8, 2018)

If you’re going to try to make it back to a Tesla I’m afraid that’s not going to work. Even if you succeed physically you won’t be able to do software updates or supercharge, as I imagine the Vin number has been flagged when totaled.


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## Riley (6 mo ago)

Madmolecule said:


> If you’re going to try to make it back to a Tesla I’m afraid that’s not going to work. Even if you succeed physically you won’t be able to do software updates or supercharge, as I imagine the Vin number has been flagged when totaled.


Actually it says it still has supercharging and full self driving. At least according to the software information page in the settings


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## Riley (6 mo ago)

Riley said:


> Actually it says it still has supercharging and full self driving. At least according to the software information page in the settings


And it’s asking me to do a software update but when I try it just sits on “starting update” then 30 minutes later gives up and goes back to the normal screen. I’ve read that it can’t do updates without the vc modules. I’ve looked at the log files on the sd card and it looks like it updates the vc modules first then the mcu


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## Riley (6 mo ago)

Riley said:


> And it’s asking me to do a software update but when I try it just sits on “starting update” then 30 minutes later gives up and goes back to the normal screen. I’ve read that it can’t do updates without the vc modules. I’ve looked at the log files on the sd card and it looks like it updates the vc modules first then the mcu


I was also able to get the mcu connected to my Tesla app but for some reason whenever I turn off power to the mcu the app switches to a car that’s not mine. It shows the vin of my mcu but everything else is someone else’s tesla. When I turn on my mcu my app will show mine but every few seconds it will switch between mine and the other one. I haven’t seen this happening to anyone else and I’m not sure what to do. I can’t contact Tesla support because their chat won’t work.


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## JasonF (Oct 26, 2018)

You're going to have a lot of out of sync firmware until you buy a subscription to Tesla Toolbox - it will let you push firmware manually.


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## Riley (6 mo ago)

JasonF said:


> You're going to have a lot of out of sync firmware until you buy a subscription to Tesla Toolbox - it will let you push firmware manually.


I also read somewhere that I can go into service mode and request firmware reinstall and that will reset everything. Is that true or does it have to be done through toolbox?


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## Riley (6 mo ago)

Riley said:


> I also read somewhere that I can go into service mode and request firmware reinstall and that will reset everything. Is that true or does it have to be done through toolbox?


If I don’t have to pay for toolbox I won’t. I want to make sure there is no other way. I already have most of the modules in the car and I got them for less than a toolbox subscription would cost me.


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## GetYourWheels (Jan 31, 2018)

Interesting build. Following and please keep us posted on this project


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## Riley (6 mo ago)

Riley said:


> I'm building my own model 3 from scratch and need help. I'm having trouble getting the vc modules to talk to one another.i am also having an issue where no audio will play. whenever I hit play nothing happens. if anyone knows a lot about the model 3 electrical system id love to get your help.











These are my issues so far. I will probably end up adding to this list as the project goes on but if anyone could help me fix those problems or answer those questions it would help me tremedously.


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## JasonF (Oct 26, 2018)

View attachment 44516


The audio might not be working because the amp isn't powering up.

The fact that the VC modules have low voltage and won't communicate might mean you have a grounding issue, or they could just be in a kind of sleep mode because their firmware is out of sync with the MCU.

You will probably need Toolbox to get them synced. As a bonus it might also tell you why the VC modules aren't communicating.

The CAN network can run without some components, but the MCU will complain bitterly about it.

Supercharging access is controlled via the connection with Tesla.

You won't be able to put the car into drive if the car doesn't pass its internal checks (HV is ready and motors are ready).


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## Riley (6 mo ago)

JasonF said:


> View attachment 44516
> 
> 
> The audio might not be working because the amp isn't powering up.
> ...


Thank you so much. Right now the only parts I have are mcu/apu, vcfront, and vcleft. When I get more money I’ll get more modules. I was hoping there was some way to reset the firmware without toolbox because I can’t afford 500 a month. I’m trying to keep the car disconnected from WiFi and lte because I know if everything starts working and I start getting errors, that’s getting sent to tesla and I won’t have supercharging anymore. As of right now I still have supercharging.


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## Riley (6 mo ago)

Riley said:


> Thank you so much. Right now the only parts I have are mcu/apu, vcfront, and vcleft. When I get more money I’ll get more modules. I was hoping there was some way to reset the firmware without toolbox because I can’t afford 500 a month. I’m trying to keep the car disconnected from WiFi and lte because I know if everything starts working and I start getting errors, that’s getting sent to tesla and I won’t have supercharging anymore. As of right now I still have supercharging.


I thought I could get audio without the amp because when I look at the schematics for the car there are speakers connected directly to the mcu. But if it’s looking for a signal from the amp anyway I guess I’ll have to get that first. By the way does the amp need to be synced like the vc modules or is it just power and audio?


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## Riley (6 mo ago)

JasonF said:


> View attachment 44516
> 
> 
> The audio might not be working because the amp isn't powering up.
> ...


also for the voltage on the vc modules, i read the voltage straight off of the connections on vcfront. the input to vcfront is 12v but the output for vc left and right is 9v so i dont think its a grounding issue. also vc left is drawing about 0.2a when the system is on, that seems a bit low to me. vc front seems to be working fine as all the power to the system is going through it and the mcu is working fine.


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## JasonF (Oct 26, 2018)

Riley said:


> I thought I could get audio without the amp because when I look at the schematics for the car there are speakers connected directly to the mcu. But if it’s looking for a signal from the amp anyway I guess I’ll have to get that first. By the way does the amp need to be synced like the vc modules or is it just power and audio?


I haven't seen the amp close up, but it's probably power and audio. It might not require a signal from the amp, it might just be that you need a certain total impedance on the speaker connections, or it won't send audio.

If you don't have wifi or LTE, of course, streaming won't play. I'm not sure if USB audio will play without VCFRONT being active and working because I think that supplies power to the USB ports. Generally though if you see the audio playing (the title listed and the little bar moving) it should be sending audio.

And speaking of VCFRONT, it could be the VC modules require the VIN to be encoded and match the vehicle VIN. That would also require Tesla Tools. To avoid paying so much for it, though, you should hold off on subscribing until you have all of the VC modules.

An expert you might be able to communicate with (but don't waste too much of their time, they're busy) is look up Electrified Garage. They might give you some info that Tesla wouldn't be willing to.


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## Riley (6 mo ago)

JasonF said:


> I haven't seen the amp close up, but it's probably power and audio. It might not require a signal from the amp, it might just be that you need a certain total impedance on the speaker connections, or it won't send audio.
> 
> If you don't have wifi or LTE, of course, streaming won't play. I'm not sure if USB audio will play without VCFRONT being active and working because I think that supplies power to the USB ports. Generally though if you see the audio playing (the title listed and the little bar moving) it should be sending audio.
> 
> ...


when i try to play audio when connected to wifi and lte, Spotify, caraoke, streaming or any of those wont let me start a song. i tap a song and nothing happens. when i connect my phone through Bluetooth I can start a song from my phone and it will show it playing on the car but i cant control the song from the car. also ive already contacted electrified garage and they said theres really nothing they can do without physical access to the car which isnt possible for me. also i would like to try a usb connection but i dont have the usb port modules or cables for that.


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## Riley (6 mo ago)

Do the charge port ECU and the security controller have to be reprogramed like the VC modules or will they just work when I plug them in? Also, I've seen security controllers A, B, and C in the wiring diagrams. Are these 3 separate controllers or the one in the center console? If they are separate where are the others?


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## Riley (6 mo ago)

Riley said:


> also for the voltage on the vc modules, i read the voltage straight off of the connections on vcfront. the input to vcfront is 12v but the output for vc left and right is 9v so i dont think its a grounding issue. also vc left is drawing about 0.2a when the system is on, that seems a bit low to me. vc front seems to be working fine as all the power to the system is going through it and the mcu is working fine.


after further investigation it turns out VC front is getting 11.9v from my power supply, the pcs bolt is reading 11.9v, VC right power bolt is reading 11.9v but VC left power bolt is a little over 9v. could something be wrong with my VC front or is the left module only supposed to get 9v and the left gets 12? I'm reading straight off of the VC front connections so I know the wiring isn't an issue.


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## Riley (6 mo ago)

This project has now been suspended due to tesla being the worst company ever. I have had an issue since I got my mcu onto my tesla account where it will show not only my car, but also someone else’s car. I do not know who this person is but I suspect they got their mcu replaced and I ended up with the old one and that’s why the VIN numbers matched. Anyway, I contacted tesla about this problem. After months of trying to find a way to chat with them (to no success) I ended up calling tesla support. I explained the issue and then I was asked for the odometer reading. Unfortunately I don’t have that info because the mcu has no drive train connected. So I had to explain how it’s just an mcu I bought online. After explaining that tesla removed the car from my account. I don’t see much point of continuing with this project when I can’t control the car from my phone. I tried asking the tesla service person why tesla is so anti repair and she refused to give an answer other than “we’re just following protocol” however she did seem very aware that they are anti repair and almost seemed to support that. Anyway, if anyone would like to help me find a way to deal with this issue, please let me know. Otherwise, this may possibly be my last post.


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## Madmolecule (Oct 8, 2018)

You seem to have a good intentions, sadly based on my experience, I didn’t think you had a chance in succeeding. Did you mention on the phone that you were trying to do this to help out the environment, ha ha like that would really matter.


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## JasonF (Oct 26, 2018)

Riley said:


> This project has now been suspended due to tesla being the worst company ever. I have had an issue since I got my mcu onto my tesla account where it will show not only my car, but also someone else’s car.


The mobile app was not designed to allow VIN-less access to an MCU - you're going to need a Tesla car body with a VIN. So you'll either need to accelerate your build, or forego mobile access for now.

You can still do it, there are just going to be some parameters you have to operate within. Watch older Rich Rebuilds videos on youtube and see some of the difficulties he went through.


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## Riley (6 mo ago)

What all modules would need to be connected for the car to do a software update? I’ve heard updating will reprogram everything but when I try it just sits on “starting update” and eventually fails. I’m thinking it fails because not all of the modules are connected to the mcu but what modules do I need? Do they only need to be connected to CAN or do they need other connections?


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## JasonF (Oct 26, 2018)

Riley said:


> What all modules would need to be connected for the car to do a software update? I’ve heard updating will reprogram everything but when I try it just sits on “starting update” and eventually fails. I’m thinking it fails because not all of the modules are connected to the mcu but what modules do I need? Do they only need to be connected to CAN or do they need other connections?


Probably all of them in order to do a normal software update. If you do a reinstall from the service menu it might only require the MCU.


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## Riley (6 mo ago)

JasonF said:


> Probably all of them in order to do a normal software update. If you do a reinstall from the service menu it might only require the MCU.


I’ve tried a reinstall and it does the same thing as a software update. The car thinks it’s at a service center in California because there’s no GPS signal so I have full access to the service menu. Also do you know what modules I need exactly? I know mcu, apu, vcfront, vcleft, and vcright, any others that are necessary?


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## JasonF (Oct 26, 2018)

Riley said:


> I’ve tried a reinstall and it does the same thing as a software update. The car thinks it’s at a service center in California because there’s no GPS signal so I have full access to the service menu. Also do you know what modules I need exactly? I know mcu, apu, vcfront, vcleft, and vcright, any others that are necessary?


I'm not sure, but I'm guessing anything that would cause a critical (red) error and would come with a "Software update cannot be installed".

Also, service mode is no longer geofenced in more recent software builds.


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## Riley (6 mo ago)

JasonF said:


> I'm not sure, but I'm guessing anything that would cause a critical (red) error and would come with a "Software update cannot be installed".
> 
> Also, service mode is no longer geofenced in more recent software builds.


When it fails an update it just says “software update could not be installed. Please try again later” an it doesn't say why it couldn’t install. Do you know how I could see what errors are cause if it to fail.


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## JasonF (Oct 26, 2018)

Riley said:


> When it fails an update it just says “software update could not be installed. Please try again later” an it doesn't say why it couldn’t install. Do you know how I could see what errors are cause if it to fail.


I don't think there is a reference for that, just looking for any red errors on-screen or in the history is the only one I know of.


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## Riley (6 mo ago)

JasonF said:


> I don't think there is a reference for that, just looking for any red errors on-screen or in the history is the only one I know of.


I was able to get access to a log file in service mode and from what I could tell it couldn’t find vcfront. I had connected all the CAN wires but vcfront connects through other modules to get to the mcu and I don’t have all of those modules yet so I had connected the vcfront CAN directly to the mcu. I’m thinking that’s why it couldn’t find the front one. But I can’t be sure. The log files I found were from when it tries to test functions of the car. Also I believe all error messages are generated in the control modules instead of the mcu because in the several months since I’ve started I’ve never gotten any error messages on the car


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## JasonF (Oct 26, 2018)

Riley said:


> I was able to get access to a log file in service mode and from what I could tell it couldn’t find vcfront. I had connected all the CAN wires but vcfront connects through other modules to get to the mcu and I don’t have all of those modules yet so I had connected the vcfront CAN directly to the mcu. I’m thinking that’s why it couldn’t find the front one. But I can’t be sure. The log files I found were from when it tries to test functions of the car. Also I believe all error messages are generated in the control modules instead of the mcu because in the several months since I’ve started I’ve never gotten any error messages on the car


I think there is a vcfront and a vcleft? Maybe they connect to each other.


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## Riley (6 mo ago)

JasonF said:


> I think there is a vcfront and a vcleft? Maybe they connect to each other.


There’s front, left, and right control modules. I know I have to have those but there are a few other parts like the steering wheel control module and a few others. I’ve looked at the CAN connections in the tesla service manual and there are some bigger parts on the CAN network like the steering rack and things that I can’t get right now. I’m hoping it doesn’t need everything for the update to work.


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## JasonF (Oct 26, 2018)

Riley said:


> There’s front, left, and right control modules. I know I have to have those but there are a few other parts like the steering wheel control module and a few others. I’ve looked at the CAN connections in the tesla service manual and there are some bigger parts on the CAN network like the steering rack and things that I can’t get right now. I’m hoping it doesn’t need everything for the update to work.


Probably not - you would just need enough so the MCU can complete its self-check without errors.


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## Riley (6 mo ago)

JasonF said:


> Probably not - you would just need enough so the MCU can complete its self-check without errors.


Well that’s what’s confusing me. It’s not giving any errors. It’s just not updating. I also tried a complete factory reset and that didn’t do anything


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## JasonF (Oct 26, 2018)

Riley said:


> Well that’s what’s confusing me. It’s not giving any errors. It’s just not updating. I also tried a complete factory reset and that didn’t do anything


Try the reverse then - unplug the entire CAN bus and try installing.


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## Riley (6 mo ago)

JasonF said:


> Try the reverse then - unplug the entire CAN bus and try installing.


I tried that. It didn’t work. It does the same thing whether CAN is connected or not which partly makes me think my wiring is wrong but I’m using Ethernet wires so it’s twisted pair and it’s all wired according to the service manual


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## JasonF (Oct 26, 2018)

Riley said:


> I tried that. It didn’t work. It does the same thing whether CAN is connected or not which partly makes me think my wiring is wrong but I’m using Ethernet wires so it’s twisted pair and it’s all wired according to the service manual


I do notice that when my car firmware updates it does things like cycle the rear motor oil pump and the coolant pump. So it's entirely certain that if it can't perform those calibrations it will fail (I just assumed it would skip them and move on, but maybe not).

The fact that it can't see vcfront though, you might have to get one of those devices that connects a PC to CANbus and see if vcfront is communicating.


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## Riley (6 mo ago)

JasonF said:


> I do notice that when my car firmware updates it does things like cycle the rear motor oil pump and the coolant pump. So it's entirely certain that if it can't perform those calibrations it will fail (I just assumed it would skip them and move on, but maybe not).
> 
> The fact that it can't see vcfront though, you might have to get one of those devices that connects a PC to CANbus and see if vcfront is communicating.


I also have no idea if any of my vc modules even work. Especially since I have the weird thing where vcfront is only giving vcleft 9 volts instead of 12. I may end up just buying proper wiring harnesses even though I would rather do the wiring myself to save money


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## JasonF (Oct 26, 2018)

Riley said:


> I also have no idea if any of my vc modules even work. Especially since I have the weird thing where vcfront is only giving vcleft 9 volts instead of 12. I may end up just buying proper wiring harnesses even though I would rather do the wiring myself to save money


I don't know a lot about the VC controllers, but the fact that it's providing only 9 volts says it might be sending standby voltage to vcleft, which means it's not turning on. Or it's only 9 volts because a resistor or capacitor is shorted.


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## Riley (6 mo ago)

JasonF said:


> I don't know a lot about the VC controllers, but the fact that it's providing only 9 volts says it might be sending standby voltage to vcleft, which means it's not turning on. Or it's only 9 volts because a resistor or capacitor is shorted.


It’s sending 12 to the right module but only 9 to the left one. If it were in standby I’d assume it would send 9 to both of them. It also doesn’t really get warm at all which is what I would think would happen if something was shorted out. Not sure how to test for that though.


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## JasonF (Oct 26, 2018)

Riley said:


> Not sure how to test for that though.


You would need to follow each step of the path from where 12V is input to where it's supposed to be redirected to vcleft. Whichever component drops it from 12V to 9V is the bad one.


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