Car CAN BUSes

Hey! has anyone here played with car can bus? I understand that there is 2-3 different isolated buses in most cars. I want to remote start and switch the climate controls on my kia optima phev

Knowledge you can share?

(I tried to install a OEM remote start kit for the gasoline version… but did not work… so now maybe I should arduino-DIYit-- pinout seems simple)

do you use canbus MCP2515 module to read the data?

not yet, I havent done anything besides trying to install that OEM remote starter (which required to interfere a lot of cables IG1 IG2 start …)

I wonder if I should make a simple board with 3 relays and a MCP (not sure what to do with the inmovilizer bypass pin tho… maybe it is just another relay)

There are some can bus shields out there, it should be pretty easy to get going. The trick is knowing what all the commands are and what they do. The manufacturer does not publish this so you either have to reverse engineer it or find where it has already been published. Some of the codes are industry standard so I think you can save some time there.

On a modern car I don’t think you’d have much luck bypassing the electronics to do the self start, the computer would probably throw some codes.

I took apart the OEM remote starter device and it is very simple, the only part I am afraid is that the Inmovilizer bypass pin is connected to LIN of this chip and TX and RX are connected to an atmel micro in the board… It is the only part im afraid of, because decoding the can part will be just time…

Lol probably better luck on a car forum to be honest. Remote starters and alarms are freaking nightmares in the automotive world. I’ve worked in shops before and if there is ever anything wrong with the electrical system the first thing to do is check for something like this installed. They are crap, almost all of them unless you have the expensive ones.

1 Like

Yeah, I am basically asking everywhere to get some overview, ideas and suggestions. I am surprised that there is no “open car starter project”.

I can see how everything is very secretive, my plan now is:

  1. expose all the wires that the OEM starter is using (IG1, IG2, start, inmovilizer, CAN-H, CAN-L)

  2. buy LIN-USB and CAN-USB dongles and record activity from those wires

  3. make pcb with aliexpress modules (4x channel relay board, LIN-UART, CAN-UART plus a ESP32) and daily test

… but ofc I wish I had 2 identical cars, and 1 I can leave parked home just to experiment and the other to use.

The automotive electronics world is very interesting. Basically there is no incentive to open source something because the potential for making money off of any given product is so high. Keep in mind they want you to buy a newer car that includes all the features.

It’s somewhat of an intentional paradox created by the manufacturer, that anyone investing enough time to reverse engineer has to spend so much time that they need to be producing and selling something to recover the investment.

The best source of this kind of information in my experience is the “tribal knowledge” contained within various forums.

At the same time, I know you are looking for a project because I’m assuming you can take it to a mechanic to install something like this for a few hundred bucks. It’s cold there I figure a lot of people have this done?

There are a ton of resources for hacking the can bus, so I’m sure you can find what you want to do.

1 Like

I think your view of the industry is quite precise. I wonder how they charge 350 USD+ for a car starter (which does not exist for my exact model… and I would have paid that) that in the real world should cost 40 USD in parts:

The defacto solution is an engine heater, like webasto. But the install is few thousands and the solution itself is not the best in my opinion.

Remote starters are “illegal” in EU, since idling the car without occupants is not allowed. Cars work with a lot of different things here, which is lame compared to US, i.e. there is no “Charge mode” in plug -in hybrids, remote opens all doors as default, not the driver and then all doors, almost no connectivity options like UVO/Bluelink since running the car without ocuppants is not allowed. Adaptative cruise control is simplified to ON-OFF (instead of upper speed limiting mode, etc). Little details that they remove.

yeah I know but since is a blackbox… I need to go ultra slow, for example if my starter is the one connecting ignition and then there is a takeover to the driver, what will happen if my relay just goes to default and disconnects ignition while the car is running because an ESP reboot :stuck_out_tongue:

There’s definitely at least some interest in playing around with CAN buses, so it’s not nonexistant, but I get the impression this kind of thing is quite niche. I did find this place though, maybe someone related to that project could help?

1 Like

Get an old car that doesn’t have can bus then it really can just be a couple relays!

1 Like

Every day I pass a neighbour’s car in the yard, which starts up at 8am and runs for about 15 minutes until he gets out. And the whole time the car is blowing smoke, and all the people passing by are cursing )
In addition to ecology there is a significant disadvantage in this venture. When I start the car, especially in frosty weather, I listen carefully to how it goes, whether the battery is well charged, no grinding or knocking. Starting the engine in freezing temperatures (-15C and below) is the most stressful for the engine and anything can happen.
As far as I understand, the hardest part is the immobiliser override and foolproofing (e.g. the car is left in gear and not on the handbrake)

Well thats an option, but it needs to be very old to not have can bus and stuff.

I will just expose wires first and sniff data. I discovered 2 things:

  1. You dont need to press the brake, tap start and then hold it for 10s and car starts

So technically it could be a very crappy approach of just getting an extra keyfob that is stripped and energized by the ESP and then holds a relay on start.

  1. Found a ESP32 project that via the OBD2 port controls most of the stuff, specially heating/cooling of the seats and steering (I imagine I could heat up everything faster if I turn on the 4 seats on max heat plus the steering) so hacking the can bus is still seductive even with the crappy 1) approach

I dont think that will pass the periodic control, in the mornings you see people just cleaning ice/snow from the car while it runs… then sitting inside until the windows are not foggy. I do that, in shorts, usually so it would be nice a head start of 10m

In canada I have seen people start fires under their engine to get it to go.

Isn’t this what they invented taun tauns for?