Running Tesla Model 3's computer on my desk using parts from crashed cars | Hacker News Reader

Running Tesla Model 3's computer on my desk using parts from crashed cars

bugs.xdavidhu.me

983 pointsdriesdep332 comments

From the article

> Tesla offers a “Root access program” on their bug bounty program. Researchers who find at least one valid “rooting” vulnerability will receive a permanent SSH certificate for their own car, allowing them to log in as root and continue their research further.

Pretty interesting. Sounds like Apple's Security Research Device Program[0], where you're loaned a rooted iPhone, but with a clear qualification criteria.

It strikes a nice balance, because to qualify you have to 1) show you have the skills to get root access anyway and 2) show you're willing to participate in the bug bounty program and get things patched.

I would of course love root on everything I own, but I can understand Tesla's motivation here since root for everyone would make vulnerability discovery easier for malicious actors. And if everyone had root on their Tesla, it'd be much easier to make naughty modifications that might catch the ire of regulators. (like disabling driver attentiveness checks in self-driving mode).

[0] https://security.apple.com/research-device/

Having shell is extremely handy for further discovery. SO handy that if they were just gonna patch the bug and lock you out, you would simply not disclose it.

This is what happened. Tesla security received tons of bug reports that required root access to identify, yet they got a vanishingly small number of root vulnerability reports. This policy fixes that misincentive.

If they don't give root, researcher may have incentive to keep vuln secret for root access. Looks reasonable.

It's a mixed bag. This only applies to the infotainment system and not the autopilot computer.

They've also revoked certificates from researchers personal cars in the past

FWIW, I think they share resources. I was able to crash the browser via a GPU benchmarking website while using autopilot. Autopilot disengaged and the “instrument cluster” lit up like a Christmas tree for a few seconds.

So I’d imagine an infotainment exploit would be able at least DOS the AP system.

> Researchers who find at least one valid “rooting” vulnerability will receive a permanent SSH certificate for their own car

It feels like this is something you should get by being owner of the car, and not have to do free speculative research for the manufacturer to get it.

As much as I tend to agree philosophically, could it not result in people making changes that endanger other road users?

I don’t think that’s the reason, seeing as a car is already endangering everyone around it by existing. More likely about keeping the tooling to diagnose issues proprietary and expensive.

Obviously, they are both very good reasons. Just because you don't like one of them, doesn't mean the other one doesn't suddenly exist anymore.

You could screenshot this and put it under the definition of “perfect being the enemy of good”

No, one can do that anyway. There is basically no real way to stop folks from modifying their cars. It can be made more difficult, sure.

This is about selling tools and access. It's another profit pipeline for car OEMs.

Perhaps it is also about liability. Otherwise, we would have people installing OpenClaw on their Teslas.

Then why wasn't it a problem before? People have always been able to install aftermarket or possibly even hacked together physical parts. If there was liability you'd expect some sort of shield blocking access to, for example, the hydraulic system for the brakes.

As it turns out though blatant irresponsibility is quite rare (depending on your definition anyway) since people have a strong self interest in not endangering their own lives or wallets. It's similar for homeowners - many states explicitly carve out a requirement that insurance companies cover DIY modifications that are within reason and this generally works out since you have a strong vested interest in not destroying your own house regardless of any insurance policy.

> Then why wasn't it a problem before?

It is. Thousands of people have died because of aftermarket headlights. Harder to assess, but probably much larger, is the number of excess deaths from nitrous oxide etc. emitted by modified cars.

There are about 3000 deaths per year in Sweden attributed to position from cars, and 300 physical accidents. So it is a really big issue, but it is almost impossible to make people understand that their car use and modification mains people.

Modified cars can release 1000x more polution, on streets with 800 daily cars that will have an affect.

You can ban modifying your car to pollute more (which we do) without banning modifying your car.

This isn't complicated FFS.

The difficulty against this in the US is the unfortunate reality that the people coming to these shops to enable their stupid trucks to roll coal are the people who should technically be raiding and shutting down these companies. This can be fixed.

Physically, you can already modify your car to be controlled by a stupid program and that has been possible since at least the 90s. You can do the supposed harm by not being aware of damage to your exhaust system.

The solution to exhaust harms of ICE engines is electric cars, not a reduction in consumer rights.

The EPA heavily regulates any emissions defeat devices. The problem is they spend most of their time going after tuner shops where most cars run on ethanol rather than diesel shops who cater to brain-damaged customers who think rolling coal is "cool"

In Spain (but I think in every EU country) you must go through legal inspection and certification if you do modify your car. And most of the aftermarket mods people install are totally illegal and would not pass that exam. I mean changes like putting a spoiler, lowering the height from ground etc

People get killed by changes to exhaust, height (lift kits), bumpers (bull bars in particular), etc pretty often, though. And I can imagine software changes (exhaust is part of that actually) could kill people too.

Maybe you think daytime running lights are stupid and want to disable them for instance.

Sure. Point is nothing has really changed. Largely there's no problem and to the extent that bad things happen it isn't something novel that's only just come up. It's not in and of itself an excuse to erode private ownership. If intervention is required then regulation should be passed deliberately by the legislature.

I dunno, I think there's a big difference between making digital modifications to software vs. making physical modifications to hardware.

The risk profile is very different and non-obvious to your average car owner.

It's the difference between trying to repair your leaky dishwasher vs. trying to repair the electrical panel in your basement.

Well both of those examples could potentially electrocute you or start a fire and both can be done by a homeowner if he feels like it.

I don't disagree that it's a bit different in certain ways but I feel like that's drifting off topic. It shouldn't be up to manufactures to determine these things unilaterally but rather the legislature. Particularly any justification to the contrary rings hollow in this case because there's a very strong conflict of interest.

That kind of thing is always the stated justification but never the real reason.

Almost invariably when that excuse is trotted out, there are are usually many things that are much more common that are also far more dangerous. For example, texting while driving or driving with bald tires in the wet are both 100x more dangerous than anything almost anybody would do by modifying the car's software.

Four 9/11s worth of people die every year from drunk driving. If we can't even get that under control, I don't see why being able to modify your own car is a big deal.

It doesn’t have to be a “big deal” for the powers that be to resolve that you shouldn’t have root access to your iPad on wheels, dude.

We could do both…

Disabling alertness sensors might worsen drunk driving actually.

Isn't this largely a US problem?

Enforcement is abysmal for stupid reasons. Courts are reluctant to remove the ability for people to drive because America purposely made itself dependent on cars, and cops are reluctant to actually arrest a lot of people for drunk driving because they tend to be buddies, or worse. You can find plentiful examples of off duty officers trying to get out of drunk driving simply by being a cop.

This is what you get when you can vote on the sheriff and judges who insist they are "Tough on crime" because they sentence a dude smoking a joint to years in the joint while ignoring real problems like, you know, murder and theft and violence and all the shit their buddies are doing. The "Tough on crime" people are the ones drunk driving often enough.

I think it was pretty clear I was talking about the United States.

You can feel that way, but plenty of car configuration has always been locked away and walled off, and manufacturers make a tidy profit selling software licenses to dealers and mechanics to perform basic diagnostics. Proprietary software is big business what can you do.

Definitely not always. It used to be that a mechanic or a skilled owner could tune, modify, repair or replace absolutely anything in your car. That was basically since the invention of the car, up to somewhere in the 2000s. And even then, various hackers and pirates made sure almost anyone could get their hands on the software. In fact, many mechanics these days use 3rd party software because the manufacturer refuses to sell them their version or even that version doesn't have all the features.

That is the recent (and gradually worsening) situation but it is not in and of itself a justification. Effectively you're saying "it's currently this way therefore it's okay for it to be this way".

Manufacturers have increasingly restricted control over products as they've gradually been digitized. Prior to the digital era anyone could do anything to personal property (regulations notwithstanding ofc); more expensive items typically came with circuit diagrams for the purpose of repairing them.

You can translate that to corresponding car-purchases, i.e. vote with your wallet.

Really? Which car manufacturer officially provides you a root access to your vehicle?

It’s almost like there’s no market for this because it’s a silly thing that practically nobody actually wants enough to vote with their wallet.

That, or no company wants to assume liability. In which case, go whine to your local representative. That’ll be hilarious for all involved.

Even as a well trained software engineer who works on transportation software including ECUs (heavy equipment not cars), I'm not sure there is much I could do with root. IF I had full source code to my car's radio I might try to add android-auto back in (it has android-automotive so I know it can do it), but if that isn't easy I'd probably give up. Without source code and a lot of time doing anything is impossible - as anyone else who works on complex software knows.

Maybe 0.1% of consumers even know what "root access" means.

Normies get scammed on Discord into pasting commands into their browser console.

As a pedestrian I prefer for most people to not have root access to their multi-ton fast-moving killing machine.

Agrred, but it is remote root access is the danger, they already have root access to the physical dangerous things.

That is blatant whataboutism. Stop performing mental gymnastics and accept that what you personally want is not what’s good for society as a whole.

It's not whataboutism, it's a legitimate question. How does it increase safety on the road to reject local SSH connections by a dumb user, when that same user can mess with the car physically?

How does adding another way to cause safety issues affect safety?

Give me root access so i can install openclaw.

Simplest example: a driver could probably disable attentive driving checks by pasting a script in from a web search in a few minutes. Nothing like an inattentive 3750 lbs weapon.

A driver could also install a little machine that turns the wheel slightly at regular intervals, to the same effect.

Yeah and they could hire a professional driver or a engineer and IPO for billions a life sized driving AI powered crypto robot too. Look, like clearly google + ctrl-v scripting or running an one click deployment exe on your computer on a whim is different than physically ordering/picking up something and then installing it into a vehicle?

Of course they're different, but you're trying to argue that the former takes objectively less effort than the latter, and it doesn't. One or the other may take less effort depending on who you are and what you know.

I've heard multiple people claim an ankle weight on the steering wheel is sufficient for hands-free driving.

Actively combated by Tesla as they detect it also. They actively apply patches to try and detect things like this and block it.

Which would get you in trouble if you were to be pulled over by the police at any moment.

IMO most of the things people would want to paste commands into their car for are just valueless rent-seeking.

In most cases I agree with this, but maybe not for potentially dangerous things like cars? What if someone roots into their car and disables some essential safety feature - maybe even a legally mandated safety feature?

More concretely, the expertise-required-to-access-root is in a different field to the expertise-required-to-make-wise-changes. i.e. you might know how to hack a car, but that doesn't mean you know how cars operate.

People have been modifying their cars since cars have existed, an electric car shouldn’t be anything new.

Given electric cars are responsible for much bigger responsibilities than combustion cars (avoid driving into that bicyclist), there are new concerns here which beg extra consideration.

I actually think we should be asking more of safety regulations here with regards to the design of electric/computerized cars.

Think of it this way: every concern you have about a teenager having root on their electric car is the same as any sociopath hacker (AI enabled for modern nightmare fuel) who finds a root vulnerability and decides to not be a good person with it. If a teenager can mess with the collision avoidance, e.g. Israel can modify it to murder anyone who talks shit about Israel in the car. Or the CIA could turn it into a weapon. Or one day some dev could push a bad OTA update. Et cetera. Our safety regulations should mandate design features to prevent a malfunctioning computer from posing any greater safety risk than any other modified part in the car.

People have been killing each other with weapons for as long as they've been around, nuclear weapons shouldn't be anything new.

No one should have nuclear weapons, we aught to have robust policy, institutions, and vigilance to prevent their proliferation and use.

Computerized vehicles aught to be strictly regulated in terms of how computers may affect the physical operation of the car, such that a reasonable standard of safety can be ensured outside the usual risk one takes when hopping in a motor vehicle. The fact that a hacker can possibly kill people by rooting an infotainment system is a symptom of the general disregard for security in design, and we continue to ignore it for engineering expediency.

Up until v recently cars were not remotely accessible and part of a command-and-control network which Teslas are (perhaps other modern cars are too, I only know Tesla because I have one).

I know that the car reports practically all user events to Tesla in real time over the cell network (eg, open door), and I know it has root access. I don't know if that root is available remotely and I don't know if foundational commands like steering, acceleration and brake are accessible via the CLI (they are computer controlled actions locally)

THUS I would not want to drive a Tesla if there was the possibility of all cars being rooted and remotely controlled by an unauthorized actor.

Not intentionally, but some cars have been vulnerable to remote control/hijacking since at least 2015.

https://www.wired.com/2015/07/hackers-remotely-kill-jeep-hig...

That’s quite a weak confidence in their own platform security if finding a root level vulnerability is not one-off event, but it’s a program expected to have multiple people routinely finding those.

Well it's a selection bias.

If an athlete breaks a world record, they're likely to do it again. Even though it's incredibly hard to break a world record.

Imagine having to hack your device, then having to submit a request to actually own it.

The interesting part is this implies that Tesla cars have static certifcates that don't rotate. (Whoops.)

Why can't they rotate ? having root ssh keys on the device doesn't imply the certs don't rotate.

Not necessarily. All they have to do is roll a pub key into the update package. Same as any OTA update.

Do Tesla vehicles get VIN-specific updates?

Not sure - if I was designing it, feels like it would be a good way of getting the right build to the right car so that all the HW versions of each module are in line.

I'd imagine that the update includes all the possible hardware, and the update script actually decides which components to use. Like apt on Debian or yum on RHEL.

Interesting - just found this: https://www.pentestpartners.com/security-blog/reverse-engine...

Not had a chance to read it properly but definitely will be!

That was an amazing read, thank you!

It appears that the Tesla is running a full Ubuntu Linux distro. And here's a small quip to entice passers-by to read more:

  > With names ranging from “INDIFFERENT” to “SUICIDE_BOMBER”, there is a list of escalation strategies in the updater binary, which appear to be strategies for retries of downloads and user prompts on the UI.

My read of the output in the post when they tried to SSH to the device was that Tesla are actually doing the right thing here and using an SSH certificate authority, which allows issuing certificates signed with a private key authorising access to a subset of devices (optionally for a defined period of time). https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Certificate-b... has more information, but in summary unless the private signing key is compromised in some way this is entirely legit. I'd hope that they also have some mechanism for distributing a new public key if the signing key does get compromised but who knows.

I understand there are also certs involved with tesla vehicles communicating with a supercharger as well.

And as we all know, if you're smart enough to get root access, your neighbours children playing football in the street should be subject to the risk of you driven a car that claims to have full self driving with custom code on it.

I used to work for a company that made third party scan tools. We had racks of ecus disconnected from the car with just a diagnostic connector and power. nothing got to a real car without first trying it on the rack. I remember on time we figured out a bmw (pre obdii) had the bytes offset from the standard documentation (it was a semi-standard protocol that some other cars used at the time), we went from we communicate but nothing is wrong to a very long list of dtcs on that controller. (All our competitors also showed nothing wrong, but the official bmw tool showed dtcs)

Diagnostic Trouble Codes?

Yes.

I spent the last week successfully reverse engineering my car / various scan tools to get the right information to diagnose a fuel pump problem (and to do so without the incredible awkwardness of many of the tools)

It's pretty amazing what Claude + Ghidra + knowledgable coaching can accomplish. It was basically just setting direction, setting up an incremental workflow with the right kind of documentation, and questioning some of its theories and assumptions from time to time.

I'd love to release a lot of it but I'm torn between releasing artifacts created with expensive software I paid for and thinking that many of those things should really be freely available to anyone (specifically the things which definte the protocol to talk to the car and mapping of what various things are reported vs what they actually mean.

Wait, why wouldn’t you post it/ write it up?

If you release it people expect you to support it an answer questions. Some of them are not even nice about it. It pays to release this only if there is a group of people who will be constructive in helping make it better, otherwise it is a thankless effort.

The difference in ethics between reverse engineering something to be able to fully use/repair it vs. reverse engineering something to clone it. Also violating a license agreement I freely accepted and exposing myself to liability for IP theft. But is the IP just gatekeeping vehicle manufacturers hiding information from owners or is the IP the creation of this tool company or is it something in between

Just dump it in a gist. That your of knowledge should be free

+1 on the "plz tell me how" train!

The prompt I'm happy to share

https://gist.github.com/cole-christensen/cb9119e2f6b0f29b568...

Sorry, what are you talking about? Just release it? Are you talking about trying to make money off it? Are you claiming you reverse engineered ecu tuning software you paid for?

You really must be new to this, huh? Expensive software that you paid for?! Claude? Yes, the question is whether you want to share knowledge that cost you literally nothing, and will bring humanity one microscopic step in a better direction - or not, feeling superior in that only you have access to that knowledge. You have a choice!

> I'd love to release a lot of it but I'm torn between releasing artifacts created with expensive software I paid for and thinking that many of those things should really be freely available to anyone

Release it or not, but either way you’re almost certainly going to get paid back the same amount of money: $0.

I’ve recently built a disassembler and emulator using Claude to help reverse engineer a 90’s ECU based on an Intel embedded cpu. It was quite impressive to watch when Claude started to use the emulator to help understand how bits of the code worked.

The juxtaposition of Claude+Ghidra being able to take apart understand and reimplement the core features of this thing in hours while also having to babysit it "no, those encrypted packets going over the CAN bus aren't from wifi" and "please actually look at the code you just decompiled instead of guessing how they work" was pretty amusing.

That's super cool, I'm currently struggling with scan tools for a 1999 Mercedes E300 Turbodiesel. I had one that worked OK for about a decade (Autel something or other) with a 38pin connector, but it recently bricked itself with a message like "connect via USB to Updata" which I assume means its firmware somehow erased itself. Cannot figure out how to "updata" it, doesn't seem to connect via USB, the Autel software runs under Wine but doesn't appear to recognize the device... gave up and bought an iCarsoft device which sorta kinda works. It can talk to every module except for the ECU (Bosch MSA 25.1 I believe?) however if I tell the device that my car is a different model (1995-1997 naturally aspirated) I can blindly clear ECU DTCs, which is good enough because this thing is barely more complicated than a toaster. All that is to say, this space is ripe for some open hardware/software love.

> All that is to say, this space is ripe for some open hardware/software love.

There's just so many computers and what-not in modern cars that this is a very tall ask. You'd need a project on-par with HomeAssistant to get anywhere.

Yeah, it seems like more modern technology has settled on standard protocols (maybe a naive impression--someone will shout at me if that's the case) but there's probably a very long tail of bizarre false starts if you want full coverage of models back to the early 90s when computers became more commonplace.

After 2006/2007 nearly everyone did CAN. I think that is even mandatory in the US, though I have no clue how to look that up (I assume there are details and exceptions) However before then everyone did their own thing. Often with custom chips that haven't been made since 2004 (or even 1999): good luck finding one that works if it breaks. CAN is cheap and allows a lot of power while hiding most of the protocol complexity. The things before that were often not as powerful as CAN, while being in practice a lot more complex because the complexity wasn't hidden.

Not sure about your specific car, but a lot of the “consumer friendly” options like OBDeleven, Carly, etc are fantastic. You often have to pay, but a lot of work goes into them and they often just work.

I remember getting that era working. I concluded Mercedes was trying to be clever in making a protocol so complex nobody else could understand it (thus ensuring you had to use a dealer) - and then discovered they couldn't debug it.

each body model (nothing to do with year or style) was different so clearing dtc but nothing else is not a surprise.

i did get that working, but I last touched it in 2007 so I don't remember enough details to be helpful. good luck.

> I concluded Mercedes was trying to be clever in making a protocol so complex nobody else could understand it (thus ensuring you had to use a dealer) - and then discovered they couldn't debug it.

lol that sounds just about right

Interesting...1999 is probably a bit early for that Bosch to be running one of the usual ECU update protocols like UDS. It sounds like it's in the bootloader and looking for a valid executable. So the FW updater is likely in the bootloader.

If you can open it up and find the JTAG pads, it should be simple-ish to use a JTAG reader to dump the image and then you can figure out the update protocol from that. It's unlikely to be complicated.

I just remembered one interesting thing that may help you if you make progress. The computer can only send a couple data items at and keep the engine running. So be careful how much/fast you ask.

Good to know, thanks for that

You don't know anything about late-90s Lucas/SAGEM GEMS ECUs do you, or Range Rover BeCMs?

I'm currently picking apart the firmware in those because it is now impossible to get replacement ignition key fobs, and it just can't be that difficult...

It was 16 years ago, and I only worked with what got to the US. I don't remember much and not those at all. I saw a few how to program key fob documents but we decided that was a dealer service and so I never implemented it. still generally just send the right 4-8 bytes and press a button on the fob in a minute. In any case it sounds like you want a different end: making a fob or bypassing them was never something I got anything on.

It's funny to hear LVDS be described as an "automotive" cable when all of my run-ins with it are for connecting laptop displays to their main-boards! (though that has a very different connector on it, and its a very general term for the signalling protocol from what I remember)

SpaceWire is also just LVDS with an uber-minimal routing protocol. It runs on a lot of satellites.

Not saying there's anything wrong with your perspective (lots of terms get in muddied waters, it's common and not a problem if everyone is on the same page), but this is what I just found on Wikipedia:

"Early on, the notebook computer and LCD vendors commonly used the term LVDS instead of FPD-Link when referring to their protocol, and the term LVDS has mistakenly become synonymous with Flat Panel Display Link in the video-display engineering vocabulary."

https://en.wikipedia.org/wiki/Low-voltage_differential_signa...

Yeah I saw that too which is why I posted my comment, it's surprising to me :) LVDS for display cables was an incredibly term in that context. Even still is sometimes despite them mostly being eDP (embedded-DisplayPort) now, which is quite incorrect hah

Incredibly what?

And eDP is a differential signal at 200 or 400 millivolts so I don't see how that's "quite incorrect". It's not "the" LVDS but it's still in the category.

The cable in the article is pretty much doing the same conflation of terms that Wiki is talking about - the automotive one is a proprietary cable that carries some protocol that uses LVDS as its signalling, so at the most basic level both it and the display cable in the laptop are 'LVDS cables' but that's also the most generic term that gives you no information about the protocol actually being carried by the cables.

Most modern laptops no longer use LVDS for connecting the screen, but they use eDP (embedded DisplayPort).

So LVDS is more likely to linger in automotive displays, while in less obsolete devices it has been replaced by either eDP or by MIPI DSI (used e.g. in smartphones).

https://news.ycombinator.com/item?id=47527015

Spoiler alert: it's still LVDS

LVDS with Fakra connectors is pretty standard in automotive for cameras and displays. The protocols used over it are often proprietary though.

Very cool. Over a year and a half ago I installed a towing brake controller in my Tesla Model Y. Found the location of the plug, how to access and the pinout online (confirmed via a voltmeter..) so the car's side felt straight forward. But then I needed to find a brake controller that can work with the higher voltage (14.4v vs the normal 12v). Then built a cable from the brake controller to the connector that plugs into the car that I found on eBay. I velcro'd the controller under the dashboard. It works pretty well. I towed my small camper several times with it last year with no issues. Yay! However my little project is nothing compared to this post. Love people hacking away. So cool.

>then I needed to find a brake controller that can work with the higher voltage (14.4v vs the normal 12v)

Put a voltmeter on the battery terminals of a regular car at 2000rpm and note the voltage. You'd be surpised (the alternator can produce as high as 15V on some cars).

Automotive transients can be wild. I did a bringup with a board that had specified 100+v range specified for transients and finicky quality requirements on the output. The power supplies took up most of the (very large) board.

14v is not a transient, if your voltage was 12v with the car running, there's something wrong with the charging system (DC-to-DC in an EV, alternator/generator in an ICE)

13-14v is normal in all 12v automotive systems as the charging voltage

If I recall correctly, a fully charged lead acid battery has an open circuit voltage of 13.6V.

So the alternator has to put out at least something higher than if it’s planning on recharging the battery after 500 to 700 amps have been pulled from it for a few seconds to start the engine.

Yeah, max CV charging voltage is ~14V, max charging C rate is ~0.2C, open circuit voltage at 100% is that 13.x range. And lead acids like to stay at 100% unlike Li-ion which likes 50% +/-30%, so "12V" ICE cars just use a bus voltage of 13-14V and wire the battery there. At any given moment, the car's "12V" bus voltage MUST be above 13.x and below 14.4(absolute max).

It's a bit perplexing that those lead acid systems are referred to as "12V" systems when that figure is effectively the 0% voltage, whereas 3.7V for single Li-ion cell is the 50% voltage.

e: also, ICE transients can be in kV range, coming from ignition mechanisms. I've heard that you can literally measure engine RPM by selecting 1/dt on an oscilloscope and dividing that by cylinder count.

The nominal range for automotive systems is 10-16v. If you are designing anything for automotive use that doesn’t work reliably in that range, you are manufacturing problems for people.

This. Most cars nowadays come with the so-called "smart" alternators that vary voltage wildly depending on the current driving conditions.

One minute you might be accelerating and the onboard voltage drops as the battery supplies most of electricity. Then, as you reach the crest of a hill and start engine-braking, the car frantically tries to convert all the available kinetic energy to electricity, raising the onboard voltage to quickly charge the battery.

>This. Most cars nowadays come with the so-called "smart" alternators that vary voltage wildly depending on the current driving conditions.

Which in practice means that they do a very miserly job charging the battery and are a ton more sensitive to a battery being in less than tip top shape so you can expect your battery lifetime to go down.

But it's a "win" because they pushed the serp belt change outside of whatever interval the reviewers who calculate TCO care about and they saved .000003mph in the process.

nit: Some vehicles can use a two stage charging system where if the ECU is not trying to charge the battery and the power draw is otherwise low, the voltage sits in a lower range rather than constantly float charging the battery. This can surprise you if you're trying to diagnose a battery issue!

Saw up to 800A on units like the FSD for the short time until the caps were full. Slow starting a SoC is a software problem, slow starting the Cs and keeping the impedance low at the same time a non-trivial hardware problem.

Yeah, this is normal. When the battery suddenly disconnects (for example of the lugs pop off) the alternator's momentum will send a massive, long-standing transient on the bus up to 100V. This is called a load dump.

I typically fault anything above 15.6V as “that’s a bit high, your alternator might be on its way out” when working on automotive / caravan / camper van appliances and accessories.

For static voltage sure. For short term resilience against static electricity these units typically are specced to endure 2kV on each pin.

> But then I needed to find a brake controller that can work with the higher voltage (14.4v vs the normal 12v)

Not understanding this sentence. Most running ICE vehicles product closer to that 14.4 than 12v. I think a standard controller would have worked fine?

you're correct. a '12v ICE' alternator generates up to 14.8-15.2v. Most automotive stuff can operate between 9ish-16ish-v , of course totally depending on the product.

of course this is just a modern interpretation. older stuff runs at 6v and some weirdo offbeat cars have a 24v/48v rail sitting around somewhere. Cop cars often had alternators that put out weird voltage ranges for certain equipment, or dual 12v for high amperage output.

Whilst cranking, an ICE car will drop to around 6 volts (then maximum power is extracted according to thevenim's theorem).

That means all computers etc will work at 6v.

> Whilst cranking, an ICE car will drop to around 6 volts (then maximum power is extracted according to thevenim's theorem).

> That means all computers etc will work at 6v.

Not necessarily all of them. Plenty of stuff will drop out while cranking; hopefully not the computers that run the fuel injection and ignition, though.

Interesting. I now know why my windshield wipers quit for a sec when my vw auto stop/start kicks back on.

Not a car engineer, but those motors can be pretty high A, so this could also just be a feature that helps the starter get as much power as it can while cranking.

Ignition switches were turning off the wipers and other such extras in the 1980s. Probably longer but I'm not old enough to remember

Some accessories are disconnected while cranking so the battery can supply as much current as possible to the starter.

The specs say no less than 6volts. In the real world when the temperature drops down to -70F or colder and batteries get old the voltage goes well below that: deal with it.

Even just a "12v" automotive battery itself is mostly dead if if actually reads 12.0V. Fully charged is around 12.6 or 12.7. If a car had an electrical system that actually ran at 12 volts, the battery would always be dead.

"12v" in reference to anything automotive is very much a nominal reference.

You are probably right. Surprisingly the first controller I tried didn't work. I assumed the voltage was too high since it worked in my other (much older) car. I found a reference online of people that tried a particular brand/model and that's what I went for. Thankfully my car isn't the model with the internal 18v battery.

You can run QtCar (the Qt-based app that Tesla uses for their UIs) on QEMU - if you have the firmware.

https://x.com/i/status/1722717318009041104

DM me if interested

Just put it online somewhere

It's on GitHub, but I want to avoid Tesla DMCA-ing it

Hi, can you DM the firmware?

I'm not sharing the firmware for legal reasons, but IIRC https://lunars.dev/ does provide them

> " I needed this because both the computer and a screen were being sold with the cables cut a few centimeters after the connector (interestingly most sellers did that, instead of just unplugging the cables)."

Can't you just solder some extra wires onto the cut off bits, rather than having to try and find a compatible cable? They've left the connectors in, and that's the hard bit, the rest is just wires

From messing around with these units from various cars, which often need more enablement than these, sometimes it’s nice to just know your interpretation of the wiring diagrams isn’t at fault when chasing down “no lights at all” issues.

LVDS implies differential signals and are designed to minimize EMI and can be hard to splice while still maintaining signal integrity. They can support high data rates (ethernet cables also use twisted pair LVDS). Theoretically this should be feasible up to 100s or even 1000s of mbps

He does that in the write-up, though it's unclear from the photos if he actually soldered it or just twisted up pairs. The discussion of part of the wire melting also raises an eyebrow.. no idea about the authors hardware experience, but I've seen software guys use piddly 24 AWG on a multi-amp circuit

I'd say low, given his surprise about "wiring looms" which have been the norm for 50 years? Nice write up though!

I'm amused reading the terms and requirements the author mentions in the bug bounty program for researchers gaining root access (under 'Vehicle Targets') - https://bugcrowd.com/engagements/tesla

"To promote further security research, Tesla offers security researchers the opportunity to retain root access on their infotainment system even after their reported vulnerability has been patched. In order to qualify, a researcher must send in a valid report describing a novel way to gain root access on a Tesla infotainment system. Upon confirmation, Tesla will instruct the researcher on how to use their existing root access to enable the researcher SSH feature, along with an SSH certificate for the researcher's public key (tailored to their specific hardware ID). The certificate restricts SSH access to the local diagnostic ethernet link. Tesla may renew the certificate as long as the researcher continues reporting vulnerabilities."

Very neat.

I'm actually somewhat surprised the OS fully boots when it's not connected to the expected vehicle peripherals

Yeah, I expected some gigantic writeup about tricking it into thinking all other systems are connected to it but maybe it's made this way so it's easier to repair without needing the whole car

I work on automotive software (not Tesla), and it's like this partially because it makes development _way easier_. Rather than needing to get a whole car to the dev team, you just give them the specific part that they're working on. Anything that needs outside features usually just fails gracefully (e.g. no speedometer or no location for maps). These are usually mocked for testing, or you add the specific ECU that provides it for your testing setup if needed.

Modern cars have tens of ECUs, so if you had to have all of them for testing, that would get unwieldy extremely quickly. Not to mention that cars are pretty resilient to having random parts failing, you don't want to lose the entire dashboard just because the ECU that provides camera data failed, or something.

I work on that software too (again not Tesla). One other thing - often the hardware we get is per-production and has a list of errata that will be fixed before production. They don't want to make too many of these for engineers because it is done in a fast turn-around higher cost factory and it is expected that once in a while things won't work at all (someone forgets to connect power to the CPU pin or something similarly stupid that requires a lot of manual wiring to fix on each one). As such you have to justify getting any controller and often share. Once the product is shipping they make many of them and it isn't a big deal to get one on your desk - but you have now moved onto the next thing and so the problem returns.

> Unfortunately I had no other choice but to buy this entire loom for 80 USD.

Fwiw, mine costs $450 from Ford. Also in the US we call this a wiring harness, with the loom being the material that goes over the wires

That particular statement is also wrong. For this particular setup you can also buy the correct cable (making sure to not get the one that inverts some pins!!!) for cheaper. Mine was around 15$.

Violet HSD Code D 4+2 Pin Female to D Female Jack Connector 6 Pin HSD LVDS High Speed DataTransmission Harness Wire LVDS Cable https://a.aliexpress.com/_EuGOh9e

Parts and labor combined that would be a 4000-5000 eurobuck job. A Nissan importer tried to weasel out of a warranty replacement on a friend's X-Trail so they first offered to completely refund options that had become unusable.

The car was full of issues and probably spent more time in the shop than on the road. Nissan finally had to buy it back after service techs failed to tighten the oil drain cap after an engine overhaul.

Say what you will about Tesla, but from a hacking point of view this is some of the coolest things I’ve seen in a while!

Anyone finding this fascinating, please check out Openinverter Forum [0]. Ton of work has been done in decoding CAN messages, DBC files are floating around, open source firmware and controllers are available for Tesla and others components, mostly inverters and chargers but there are overlaps with the VCU and displays as well.

[0] - https://openinverter.org/forum/

It's funny how the biggest problem turned out to be a mostly mechanical part, the rather trivial 6-pin connector.

Given the presence of the wiring schematics and the mechanical dimensions, I'm surprised that the author did not try to 3D-print the mechanical parts of the connectors, givem that the electrical parts extracted from the BMW connectors did fit.

Congrats, OP has recreated a test/development bench, the bane of developers working on automotive software development all around the world. They're so close to being a real vehicle that you think you'll be able to get a lot of work done, but they're not, so you don't.

Honestly I love it. Few things develop a more fun camaraderie than a bringup bootcamp with two precious/priceless new samples on a large conference table, and everyone being very careful to keep cups/mugs very far away.

And a soldering robot with a specialist a few rooms away to beam down the latest errata into physical form, at times.

Tracy Kidder just died, and Soul of a New Machine was a favorite of my formative years as an engineer. Once I started in headunit ECU development it felt very familiar to me at times.

I'm a software guy, but the gear has a lot of allure.

Haha, don't forget your wristbands.

Soul of a New Machine, absolutely awesome book!

Can confirm. We are required to test all of our stuff on a bench, but no one really trusts this, because everything is mocked anyway (RSI).

> We ordered the chip and took the board to a local PCB repair shop, where they successfully replaced it and fixed the MCU.

What is a "local PCB repair shop"? All the guys who used to fix TVs and radios are gone. Anyone else (not living in China) having trouble locating such an outfit in their neighborhood?

Cell phone/laptop repair shops.

When I’ve brought atypical stuff in to be repaired at one of those shops they have been absolutely willing to solder whatever, however they did have just one “soldering guy” for every shop in the metro area who only came as needed. So just keep that in mind if you’re in a hurry or want to talk an atypical task through with someone. Probably call ahead.

> A DC power supply capable of providing 12V

Hey, I just remembered my school used to have ages ago some cool power supplies (I think from Agilent?) that were very idiot proof, they had current limit with a dial that I think didn’t went over 1A or perhaps even less, and they would instantly disarm on short circuit (and indicate it with a led), and also the voltage dial I think wouldn’t go over 25V. I remember it was very big and heavy, but it survived countless students that used the lab daily.

Nowadays, is there any power supply available that is that resistant or is the recommended approach to get an used old one? Does anyone have a power supply at home that is also used by kids with a brand/model they would recommend? Thanks!

Those were called something like desktop power supplies.

https://www.mouser.com/c/power/power-supplies/power-supplies...

AT $5k it better make me breakfast, too.

They have variable dc power supplies on amazon on the cheap.

If you want that sort of reliability it will probably go towards 100$.

What you're describing is a lab power supply. (The "instantly disarm on short circuit" is overcurrent protection, which is a standard feature.) The name brands like Keysight or Rigol are kind of expensive, but there are a lot of no-name models on Amazon which will do the job well enough.

Keysight == Hewlett-Packard Old School.

Or Agilent, at some point in between

{Keysight, Agilent, Avago, HP, HPE} are/were all HP

Thanks! I had a BK Vision or something similar at some point and it just blew up. I will give it a search for these brands, sometimes I find a well-cared used one from the more expensive brands at good prices so that’s what I will look for first. :)

Got this for ~50$ a while ago. It works perfectly for this exact setup (Tesla MCU on a bench), tested it, and used it for a lot of other projects.

https://a.aliexpress.com/_EvT5Kog

This is awesome. Curious if these are plug and play and if that's the case where is the memory that tells you what the mileage is. If it's attached to the computer than the mileage would be off if you switch/repair it.

Completely unrelated. Would be interested if you figure out how to retrofit the new adaptive shocks on performance models to the older cars. Something I would love to do if I had hobby time. I'm pretty sure they fit physically, but needs to be connected to the main computer. I likely would never touch the main computer unless I got root access. In my brain I was thinking about a separate system made with raspberry pi's.

You can, at the very least, retrofit the Juniper suspension onto the old car [1]. I haven't ridden in the new Performance yet, but I recently got a 2026 Model Y and the suspension is night and day compared to my 2024.

[1] - https://www.youtube.com/watch?v=EahoyTgkkyU

That's awesome, I had heard about the new Juniper suspension on premium models retrofitted. I have a 2022 YP and didn't want to change the ride height so I wanted to retrofit the juniper performance shocks. I plan on keeping the car forever so it might be a thing I try to do in the future since it's likely to fit based on the video you sent. I haven't seen any videos on the performance retrofits. One option is to not have the electronic damping and keep the shocks disconnected, but then it will stay on whatever default mechanical setting there is. I could go with aftermarket of course, but this just really piques my interest for some reason.

ECU software development is sort of my day job. If you're going to go down this path, I seriously recommend getting the specialized plugs and connectors and making your own wiring harnesses to whatever size you need. It's absolutely easier than manhandling a full wiring harness or cutting one down. Cheaper, too.

The author mentions not being able to get the connector in single digit quantities, seems pretty specialized.

That sorta surprised me. Once I could identify a connector type from a schematic, it was almost never a huge problem getting them in small (1 to 5 piece) quantities. It's mostly a question of finding the right distributor.

Interesting.

> A REST-like API on :8080 which returned a history of “tasks”

I am curious to know what kind of historical tasks- since it's a media control unit; does it show what kind of media was being played in the last trip? does it reveal any other info about the driver?? There might be a privacy angle here that you could exploit and share it with Tesla.

They hit Odin. Odin is the diagnostic tool of Tesla. The tasks they've seen are like "TEST_BRAKE_X_STIFFNESS-TEST-PRESSURE-BURNISHED" and are used to test different components of the car. They're also used for example to reset FSD strikes.

In Tesla terms, the infotainment does much more than just playing music - it has full access to the rest of the car.

I remember back when Chrysler did that and researchers were able to shut a Jeep down mid-drive by attacking the internet-connnected infotainment. This doesn't sound great.

You need to be physically connected to the ethernet port and service mode must be enabled. On top of that, to run these you need service mode plus, which requires a subscription (signed JWT). Additionally, IIRC, most of these can't be run if the car is not in park.

I have no wheels and I must drift

> Turns out that actual cars don’t have individual cables. Instead they have these big “looms”, which bundle many cables from a nearby area into a single harness. This is the reason why I could not find the individual cable earlier. They simply don’t manufacture it.

Typical setup for cars (and lawn mowers). As a software guy my first instinct is, computing power is cheap enough, seems like a CAT5-like thing running between all components would do it. Speaking as a software guy - meaning I'm probably missing a lot of the big picture. On the other hand, it's a lot easier to safety-check a mechanical lockout that physically opens a circuit, than something running on software.

Cars are moving towards something like that, mostly because copper is expensive and there are miles and miles of it in even a basic car these days

I read somewhere that the reason they don't typically use IT networking cables / tech is because normal IT infrastructure is a lot less strict with things like packet loss. It's actually not a huge deal to drop packets here and there, especially if any given component is at capacity. But in a car, some devices are super chatty and you can't be dropping packets much at all.

That said, I'm sure there's gotta be a better way to solve it with less copper. And I think they did something like that with CyberTruck.

> ...in a car, some devices are super chatty and you can't be dropping packets much at all....there's gotta be a better way to solve it with less copper.

I know CAN is a thing for a while now, and in the aviation world they have ethernet-derived standards like AFDX etc. But for some reason cables abound.

Meh, even in the IT industry cables abound.

"tuner" almost certainly refers to a radio (think AM/FM/SiriusXM) tuner module

People need to request the source code.. There’s a ton of open source they use that forces Tesla to give you source if you’re a customer and you ask. I don’t get why security people aren’t doing this already.

You get the linux kernel and a bunch of other things you can find on github anyway. You can't do anything useful with that, except what you already can get from any linux package manager.

Sure someone should do it just to verify the process works, but it isn't really useful. (in general companies are very careful to not violate GPL license terms, often refusing to use GPL3 at all)

I love that it has a standard RJ45 ethernet connector.

I thought I saw an HDMI connector, but maybe I was wrong.

Ha! Reading this comment made me curious, so I went back and looked at the article and there does seem to be a full sized HDMI connector. I wonder if it is enabled, or just for Tesla internal testing?

It's only a debug port and not actually HDMI signaling, unfortunately.

i wonder if usb-c next to is like these diagnostic ports on Dell servers?

How many PoE adapters would it take to charge a Tesla?

Mostly depends on how fast you want to charge.

I _do_ find it weird that the LCDs from crashed cars are so expensive. I wonder if newer models have better screens, so people with older cars upgrade? Or if they're a common failure point?

I have a Model 3, but I can't say I follow the forums.. but I've never heard of screens failing -- I'm sure it happens but I think if it was common problem I'd have heard of it.

I'd guess they fail not on their own, but because they are human interface devices and take the brunt of abuse... e.g. iPhone screens are a popular repair despite being reliable components.

Some newer models have better (bigger) screens, and some are incompatible since they've slightly changed the connector. Old models (pre highland/ jupiter facelift) have used the same display shown in the article for a very long time across M3 and MY. What usually happens is that they physically break because people are not that careful, so the touch screen ends up breaking - although you really have to put a lot of force to break that display.

My 2016 Model S LCD panel developed the well-known fault of delamination and leaking some kind of sticky fluid.

Turns out the early Model S vehicles used consumer grade LCD panels that weren’t designed for the prolonged high heat you get in a metal and glass box left outside in the sun all day.

Tesla since upgraded their vehicle screens to proper automotive-grade LCDs which are excellent.

My point is, automotive-grade hardware is higher spec than regular consumer computer hardware, hence the high prices.

As an aside, I upgraded my whole computer and screen from MCU1 to MCU2 and it was worth the upgrade.

Credit to Tesla for building a retrofit computer upgrade for old vehicles. Thats a non-trivial thing to engineer and I appreciate their effort. Other car manufacturers would prefer you were compelled to buy their latest vehicle instead.

I have a 2023 model 3 and my screen had a small defect develop, a slightly darker area in a roughly half cm diameter area. I think most people would have never noticed but I pointed it out to Tesla service and they replaced the screen.

I see in the attached SS that the car has the "BIFL" FSD (?). Does this mean you could swap this CPU a non-FSD Model 3 and get it?

Excellent detective work. I had no idea you can get a Tesla's computer off market. I wonder if these may be the last decade that we may be able to get root access to our on hardware consumer products. Keep the good work up.

Granted, I think it would be valuable to look at all sorts of automotive ECUs. I always wonder how the tuning industry does their thing; I shudder to think they're just sitting there flipping hex codes directly in running software...

Makes me think imagine finding a crashed drone somewhere and you pull its guts out, use it for the home automate something, run a shed, plot point in a story

It could be clout like "I turned a Shahed into a gaming PC"

I feel like maybe you're headed towards this https://youtu.be/K9a2_3XObNI?si=vkP_utLfo3M0LFGO

I would love to use the drive units from a Tesla in a conversion project. Unfortunately, they're cryptographically paired with the main computer, and there's no way to use them.

What a waste.

The trick is to pick up the main computer and the paired drive unit(s) by picking up a whole vehicle (with a salvage title). There are shops in LA, and elsewhere who do conversions this way.

That is done to kill the "chop shops" criminals used to steal cars and then break them up for parts. You can't do that with computers because of that pairing and so stealing a car pays much less and in turn is less common. (it still happens, it just doesn't pay as well)

These conversions are super common. What am I missing?

I am surprised that they are surprised that car wiring diagrams are online. People wouldn't accept cars without online service manuals and schematics, and some states mandate them by law. I just looked up this subsystem for my car via my public library. https://appcontent.chiltonlibrary.com/chilton_images/Honda/E...

Just peruse the comments here to see how difficult they are to obtain on many cars.

You're going to make it drive an RC car right?

Nice read. I would LOVE for someone to dump the whole FSD AI/ML model and try to run it in simulator! That would be awesome!

Any way to make sure my tesla hasn't been rooted and modified by previous owner, perhaps with remote access?

Fun linguistic quirk: Americans tend to call it a "wiring harness", whereas Brits prefer "loom"

So what do you call the tubing around the wire bundle? That’s what we call “loom”.

In Canada we generally call it the sleeve, or the wrap.

I'd understand either of those, but I'd go with "tubing"

https://www.3m.com/3M/en_US/p/c/electrical/wire-cable/tubing...

That's heat shrink tubing, but we're talking about one of these:

[1]: https://www.holley.com/products/engine/engine_dress_up/hoses... [2]: https://www.oreillyauto.com/detail/c/dorman-conduct-tite/lig...

For performance vehicles I used adhesive-lined heat shrink tubing for basically everything.

[1] Braided tubing and [2] conduit, respectively.

And, of course, Germans have a dedicated composite noun for it: Kabelbaum (literal translation: cable tree).

I always like to point out that Germans don’t, in fact, have a word for everything.

It’s just a phrase or sentence with spaces removed.

Knowhatimsayin.

In German that's called Wortbildungsfähigkeit, or in English, WordStructureCapability

As a result of this and the child comments…

As an Australian. I often find myself saying things like “the wiring hardness, or loom, or cable, or whatever were calling it this week”.

Exasperated by living in a state other than the one I grew up in. South Australians are often easily spotted by their pronunciation of certain words.

Great project. This begs for real-world feedback though. A go kart would be fantastic.

Really cool breakdown. You’ve got a full Tesla gaming rig now!

I was really surprised to read this at the end of the article -- how could someone be this deep into a project of this depth and not realize this?! Not only because all cars (...er... all vehicles) are wired this way, but also because the documentation they were referencing has plenty of detail to show this... there's even a whole picture of it (and to Tesla's credit they have amazing free docs): https://service.tesla.com/docs/Model3/ServiceManual/2024/en-...

> how could someone be this deep into a project of this depth and not realize this

I think this is a software guy who occasionally dips into hardware things (to hunt bugs).

That's what I figure -- but it was wild to read that after reading the part about component-level PCB repair lol

Yeh, it seems odd to have the cut off cables, the wiring information...and then to go and buy a loom rather than bodging a cable at that point.

I will say I’m surprised how far apart the two boxes are in the car. I guess they’re not where I thought. I would assume they’re both up near the dash.

The passenger side kick panel or behind the glove box are two very common places for vehicle computers -- some cars have them under the hood, which I always thought was a bad idea.

My RAM truck with the Cummins diesel engine has the engine computer mounted on the engine block. You'd think the heat and exposure to the elements would make that a bad idea, but I suppose Cummins knows what they're doing.

Hehe I was thinking about FCA/Stellantis vehicles when I wrote that. I know it works and there are components made to work in that environment but it always felt intuitively wrong to me. Especially when the other side of the firewall is a much better environment and not far away

It’s because when placed inside the engine bay, the large wiring harness is shorter, which is not only cheaper, but also shorter wiring helps with the consistency of electrical timing and reduces noise.

Yes they do. They can tolerate engine bay heat, but not exhaust heat. They are usually shielded from getting soaked.

Some Mazdas put the metal-cased engine computer in a plastic air box that feeds cold air from the front, to help ensure the engine computer stays cool enough.

In general, I believe the cooling airflow from the frontal air and the cooling fans keeps engine bay in check.

For example, this is the board that’s used in Mazda CX-5 2017+ engine computers (mfr Denso), it lists max temperature range of +150C: https://www.renesas.com/en/document/mah/rh850e1l-users-manua...

Yeah, on the Cummins the ECU is mounted on the intake side of the engine away from the exhaust and turbo and toward the front right under the fuel injection pump so it gets lots of cooling air.

This thread is interesting to me 'cause I'm also a software guy and recently took a job dealing with building fighter jets and the amount of engineering going into the wiring and computers on those things is insane. It's been a very interesting learning experience.

My car has it under the passenger seat.

Sounds alright until you realize after spilling a bunch of flower vases in the trunk (hatchback) that the computer has literally no case on it and immediately shorts out while driving. Or a passenger spills a drink in the rear seat cup holder.

There is now a recall notice to pull the back seat out to install a $5 plastic cover over the thing.

And yep, it’s the main computer for the car which controls the electronic transmission etc. Immediate full on engine-shuts-off at speed on the freeway and you require a flatbed to tow it away level of broken. I’m sure the engine ECU is in the engine bay, but holy hell what a surprise!

I had a car with an all wheel drive computer in a similar spot in the late 2000s.

I had a small crack in the rubber seal around my sunroof from parking outside in the elements. When it rained, water seeped in, made its way down the a-pillar, pooled under the seat, and fried the computer.

Expensive fix but I was able to drive it to the shop.

Could be because they sale crate engines.

If you'd like the cursed location for a vehicle computer, have the Smart fortwo's SAM. It's the fuse box!

It's also notorious for having awful solder connections and failing outright.

https://evilution.co.uk/mod/sam-unit-solder-repair.htm (and Aging Wheels: https://www.youtube.com/watch?v=n8AAleKR33Q)

Even if you know that cars consist of a single wiring harness, it's not implied that they aren't modular and the individual cables cannot be purchased separately.

Cars usually consist of multiple harnesses -- as it is in this case as well. The harnesses are the cables in a car. That is the part you can purchase because that is the part.

There's a list of them here: https://service.tesla.com/docs/Model3/ServiceManual/2024/en-...

Software people tend to overestimate their knowledge of other disciplines, writing it off as "easy" or work beneath them. Being overpaid compared to your peers certainly doesn't help dispel this feeling. Some people have built entire careers around designing wire looms.

There's a reason that John Salvatier's 'Reality Has A Surprising Amount of Detail' blog entry is so evergreen on this forum.

> Software people tend to overestimate their knowledge of other disciplines, writing it off as "easy" or work beneath them

You should see what happens when someone involved in the sciences, e.g. Chemistry, gets their hands on Claude Code.

What happens?

A professional scientist I know (tenured, professor) recruited me to set up a backtesting framework for a predictive finance model. When the results were not as they expected (this person does not work in finance and never has), they asked to see the code, then told me that claude had found a problem with the way some of the calculations were done (there was actually no problem), supplied the claude comments, and told me to change the code to match what they thought was correct. I did it anyway. Had they had more expertise in the domain (finance), they likely would have been able to leverage claude as a tool rather than inadvertently pursuing a very stupid mistake. Domain experts tend to doubt their ability to excel in other domains which is amplified by LLMs.

I work with a bunch of PHD's and have been since before ai coding.

Their code is aways terrible, and they constantly think it's good.

The exercise is always the same: explain the math to me, like I'm 5, then we profile it and see what is faster.

Oddly Claude Code, integrated into their IDE's has made this situation happen much less.

I never want to work in a place again where the fun way to start the Monday meeting is a "math problem".

PS: Don't even get me started on their SQL.

My first job out of university was at IBM wrangling a prototype some research PHDs had written into a shipping product, and.. yeah, this tracks.

This sounds rather similar to the form of scientific fraud where you first create a conclusion, then invent/manipulate the data until it supports your conclusion.

They suddenly act as if Claude has awarded them with a second PhD in CS. Now they know everything and everything you tell them gets filtered through Claude.

It's like "software dude thinks he can do hardware", but on steroids. They don't know what they don't know and they think they have a panacea in their hands.

Don't you know? Software is beneath them and the fiddly bits are just standing in the way of them getting their BigImportantWork™ done.

Consider whether this is an uncharitable comment --- someone with little expertise in a discipline has made a rookie mistake and didn't realize that the wires weren't produced individually.

Professionals overestimating their knowledge is a very common thing!

Fair, but software engineers are especially known for this. There was an XKCD about it

https://xkcd.com/1831/

What a rancid comment. The first thing you can think of when seeing someone earnestly sharing their learning process, is to insult them of being vain.

He's right about the rest. We software people can definitely be annoying.

All people are annoying. It's still mean spirited in this instance. The author is likely reading all of these comments.

Try working on a software project as a non-developer and see if you still respond so negatively to their sentiment. I can’t tell you how many times developers tried to arrogantly and dismissively explain design principles to me, as an experienced, degree-holding designer, because they skimmed a whole Tufte book at some point.

I was a developer for a decade before I went to school for design, so I’ve seen it from the other side. It’s not all bad: that overconfidence can lead people to tackle problems they’d abandon if they really understood the domain’s complexities. But often it presents like developers acting like their genius developer brain allows them to solve difficult problems in completely different fields with a few glib analogies and a few brief thought experiments.

I don't know, I've had more non-technical people and trades try and mansplain bullshit they don't understand than tech people have.

People tend to overestimate their knowledge of other disciplines.

I have worked with a LOT of PHD's in recent years. Their code leaves much to be desired.

It's called misplaced confidence and it isn't exclusive to software engineers. Doctors, engineers, presidents... The list goes on.

> and to Tesla's credit they have amazing free docs

Not to Tesla's credit, they had to be dragged kicking and screaming into it (primarily by Massachusetts) and their right to repair legislation through a solid chunk of malicious compliance:

1. When told that they had to have a site for people to order parts, Tesla put up a site that had every single item as "Call us", including the most simple of bolts. And when a few places called, "Sorry, that's not available to you".

2. The service manual was originally only available in a few locations in MA, and had strict conditions: you had to book in advance, there was a $100 fee per booking, and you could only view the manual on premises, and could not bring electronic devices into the room with you, just pen and paper.

The docs they have are great, and who knows how their attitude would have changed over time, but they absolutely didn't want you to have it, initially.

Tesla treated the service manual like congress treats certain recently surfaced files.

Wrong. They’ve always been open, even with their patents too. All free to use, no royalties

Confidently incorrect.

https://www.reddit.com/r/teslamotors/comments/utivlj/tesla_s...

> This used to cost $3187.50

https://driveteslacanada.ca/news/tesla-service-manuals-free-...

> The access story has been inconsistent over the years. Tesla has opened up free access to both the service manuals and diagnostic software in the past, but that was apparently a mistake, and loopholes were quickly closed.

https://www.teslaownersonline.com/threads/tesla-service-manu...

"Always ... all free to use". Not so much. And before that, even less available.

I will grant you for number 2, there seems to be some ambiguity - some people claimed it was only if you needed to actually use their diagnostic tools, because Tesla wouldn't sell them to anyone at the time (which is also in contradiction to your "everything you need, all free, always").

Diagnostic tools are built into every car and free, service mode is amazing. No other car manufacturer does that.

Elementary diagnostic tools are free.

If you think this is actual diagnostic tools? No.

Free? Weird that Tesla offers a subscription for it: https://service.tesla.com/en-US/diagnostic-software

$700/year is a strange definition of "free".

You seem to miss my point. The OP wanted to pat Tesla on the back for their amazing commitment to freeness and openness. My point was that even if they are doing good/much better now, much of the time they had to be dragged kicking and screaming to it. MA's AG had to wave the right-to-repair laws.

It's not uncommon knowledge that third party repairs have been, for years, difficult to impossible because Tesla wouldn't supply either the information or the parts to third parties. I'm not sure why, in the face of repeated evidence otherwise, you seem determined to retcon those details out of existence.

No, you’re wrong. I have a Tesla and service mode is free and amazing, I can look at any system and subsystems with it, look at logs, and do testing, all from the built in touch screen all for free. No other car manufacturer comes close. Not sure why you hate Tesla so much and are so bent on spreading false information. Maybe you should help save the planet and get one.

Maybe you should read Tesla's own documentation. The service mode you have is an elementary version of diagnostics. There is an actual diagnostics mode that costs $700/year to have access to.

Again, since you plainly didn't read it: https://service.tesla.com/en-US/diagnostic-software

service.tesla.com - if I'm spreading false information, so is Tesla. Oops.

Is plenty enough to do full diagnosis on the car. Far better than any other manufacturer does. Give me one that’s better.

Makes you wonder why they sell that, then, huh. Obviously nothing fruitful is coming from further interaction here.

Well the AG has a lot of work to do then, because basically all other manufacturers are charging thousands for any sort of diagnostic manuals

GM service manuals for instance are $1,344.00/year.

Ford service manuals are $2,834.95/year.

Honda service manuals are $1,500/year.

Hyundai charges $600/year.

Toyota service manuals are a steal, they only charge $580/year.

I'm sure you're an expert, pro at everything.

Yes I am. Thankyou for recognising that

I wasn’t criticizing them.

EVS have actually managed to reduce the number of wire bundles (mostly due to switching to Ethernet instead of CAN Bus)

Tesla also went to a 48v wiring harness in some of their vehicles to allow them to power more equipment with less copper. It might be one reason why they use nonstandard connectors, so people don't attempt to hook 12v equipment to the system and also the higher voltages might require connectors rated for it.

Now they just have to take the next step and have everything in the vehicle running on PoE.

How?

When canbus is already two wires, and by definition, is a bus, so you can just keep stringing those two wires to any module you need. I know Ethernet BUSes exist, but what advantage would those have to canbus then? They're both two-wire buses.

Canbus is much slower than single-pair Ethernet. So you can get more data (more modules connected) over a single pair of wires if you switch to Ethernet.

> I was really surprised to read this at the end of the article -- how could someone be this deep into a project of this depth and not realize this?!

Usually, for most other vehicles, the connectors are either standardized (e.g. radios, ISO 10487 [1], high-current chargers by VG 96917) or the foundation plugs, sockets and re-pinning tools are readily available by the vehicle manufacturer or by aftermarket suppliers.

Tesla truly went out of their way to make the life of third parties (such as wire harness repair shops) more miserable here.

[1] https://de.wikipedia.org/wiki/ISO_10487

I was more fascinated that a new wiring harness was $80! I've easily spent $30-50 for a single VAG cable 1ft pigtail.

This is cool, how exactly did it boot?

Could 'lb' be load balancer?!

It actually stands for "lizard brain"... it is (or at least was) an Infineon Aurix control and monitoring microcontroller, they may have changed to a newer one.

Prime example of free will

But can it play doom?

It could probably run it and learn to play it too.

this is the coolest shi i've ever read on hackernews

Digital Optimus on your desk! /s

Very cool.

Now why didn't an AI think of that? :)

Human have a better taste (at least for now :D)

i wish the ui on those things was more visually appealing. between the cheap looking gloss finish on the display itself and the unextraordinary ui, it's just kinda blah. one can have a debate about to screen or not to screen or whether to use vfd displays or whatever and i get the importance of cost control but it should look good and it really doesn't. the graphic of the car looks like a cartoon.

Interesting take–– I feel the total opposite; I love the UI.

i think a lot of people do. i don't know what it is, there's maybe just something about the car graphic that doesn't sit right with me. the front/side view when parked just seems cheesy for some reason. maybe because it's meant to show unclosed doors or something and when everything is set the car's status is car which is redundant.

It does show open doors etc. but if not that then what would you show on the screen? You can already shrink it so the rightmost 3/4 of the screen is the map, leaving just 1/4 of the screen for the car visualization and indicators.

maybe it's the quasi-photorealistic nature of the car image that bothers me. it's not a photo, it's not a schematic, it's not a diagram. it's too artificial to look like a photo, yet too realistic to look like a schematic. or maybe the physically implausible lighting.

Animations could probably be faster and touch areas for opening trunk/frunk could be larger.

But then I'm driving brand new Fiat RV with CarPlay this week. Cruise control by itself has 2 or 3 bugs, and that's not even trying to be picky. Or how's this - can't hotspot from me while phone is in carplay. Can't pinch-zoom or pan maps in 2026 and myriad other things that makes me cringe when people moan they don't buy Tesla because lack of carplay.

It's glass...

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