What is possible?

Hello everyone.

What is possible with the CAN bus?

Can I, for example, open the central locking system using the bus's controls?
Or even start the engine?

What else is possible with the appropriate electronics, and how should they be designed?

Can this be made universal, or do I need a separate version for each vehicle?

Thank you in advance, and I look forward to the discussion.

Hello everyone.

What is possible with the CAN bus?

Can I, for example, open the central locking system using the bus's controls?
Or even start the engine?


Hello,

Everything is possible .

At least, some strange things have happened to me with Mercedes cars.
- w204: Comfort-Can: The engine stopped working after the CAN driver in my CAN-Bus interface failed after the engine started, which disrupted the CAN-Bus.

- Bus: I accidentally played back a trace from the engine start-up process, and it actually started the engine.

Conclusion: Uff, that's it .

Regards,
Andi.

Can you give me a general overview of how this works?

So, how do I get the signal to start or open the door, and what do I need to feed power back into the bus ?

You're welcome.

Hello.

- Bus: I accidentally played back a trace from the engine start-up process, and it actually started the engine.


And the Earth is flat?!

What is possible with the CAN bus?


Hello,

Please provide the German text you would like me to translate.
Within a bus system, control units (nodes) transmit not only application messages ('status' of the control unit) but also NM (Network Management) messages according to standards such as OSEK, AUTOSAR, and NM-High.

2)
The control units also send diagnostic messages when they want to influence other control units or are queried by other control units.

3)
Almost every control unit has a unique ID, which allows it to be accessed through diagnostic messages.

4)
Diagnostic messages are not only used to read values (e.g., error codes), but also trigger actions within the control unit (ECU). (Possibly also activate window lifters, engage central locking, etc.)

5)
In principle, communication with control units can only be achieved from the outside via the gateway and diagnostic messages. Certain 'sensitive' areas of the vehicle are protected by requiring specific codes (manufacturer-specific and potentially vehicle-specific) to perform certain functions, such as clearing error codes.

6)
However, it is also possible to directly 'interconnect' with the CAN bus and trace the traffic (after the gateway). For example, if you trace the startup phase in the bus system, where the engine control unit (ECU) is located, you can disconnect the ECU from the rest of the bus and send the recorded trace directly to the ECU (play it back), thereby simulating the rest of the bus for the engine. This will cause the engine to start.

-> The Earth is round, you know!

Hello,
It probably won't work that easily.
How do you know, within your trace, which messages are coming from the engine control unit (ECU) and which are being sent to it?
If you simply "play" a trace file, the engine control unit (ECU) is more likely to be confused than to start the engine.
As long as you don't have a basic understanding of the messages being sent from the engine control unit (ECU) and the responses it expects within certain timeframes, this is likely just wishful thinking.

Greetings.
Jens.

Hello,
If you simply 'play' a trace file, the engine control unit (ECU) is more likely to be confused than to start the engine.
As long as you don't have a basic understanding of the messages being sent from the engine control unit (ECU) and the responses it expects within certain timeframes, this is likely just wishful thinking.

Greetings.
Jens
Hello,
This isn't wishful thinking; as I mentioned before, the engine started (which, I have to admit, surprised me at first).

Basically, you just need to tell the engine control unit that you want to start the engine. And if the ignition key signals are not transmitted analogously to the engine control unit, there is a very good chance that the engine will start.

Regards,
Andi.

If you simply 'quickly' play back your trace, the engine control unit will likely feel like it's being tricked, rather than starting the engine.

The engine control unit (ECU) will not be fooled, as it normally does not re-check its own transmitted messages in the trace.
Normally, the checks involve verifying the cycle times of messages that are 'important' for this device, as well as NM (Network Management) messages, and certain data integrity criteria (e.g., specific message counters for certain incoming messages, checksum calculations as an additional measure). Signal in the data field, etc.)
If you 'play back' the trace, you will only see that you have 2 engine control units (ECUs) in the network (1x Tx as a simulated device and 1x Rx as a real device that responds to the rest of the bus simulation).

To be honest, I haven't seen a car yet where the engine is started via CAN.
That's quite a huge fairy tale.

To be honest, I haven't seen a car yet where the engine is started via CAN.


I have personally handled several engine control units that perform this function.

This fairy tale is also narrated by Wiki. Simply search for the 'engine control unit' there.

OK...
I really don't want to argue with you or anything... please don't misunderstand.


Basically, someone replayed a trace, which allowed them to start their engine.
This scenario is impossible because all 'important' CAN messages in the drive CAN contain checksums and keep-alive counters.
The checksums are calculated, among other things, from the date and time, as well as the keep-alive counter and the mileage.
While it is technically possible, it is about as likely as winning the lottery with a 6 on a full moon.

If it was a VW, then it can be excluded with 100% certainty.


It bothers me somewhat that, in some cases, extremely superficial knowledge is being presented to people 'as fact.'
Everyone can and should make their own assumptions and explore in all directions.

However, if someone claims they rewound the trace and the car then started working, that is simply untrue.

Somewhere, I also read that someone triggered the airbags via the CAN bus.
I believe that wasn't here, though. That really makes me furious.

Generally, these forums are about sharing information, helping each other, and showcasing achievements. Half-truths should be off-limits.

Sure, here's the translation:

'Just my 2 cents.'

OK...
If it was a VW, then it can be excluded with 100% certainty.

It bothers me somewhat that, in some cases, extremely superficial knowledge is being presented to people 'as fact.'
Everyone can and should make their own assumptions and explore in all directions.

However, if someone claims they rewound the trace and the car then started working, that is simply untrue.

I also don't like to argue , so here's my final statement on the subject:
1) It wasn't a VW, but a Mercedes bus.
2) I don't like being portrayed as a liar, and when I write that the engine started, then it really did. So, it's not a guess, but a 'fact'!
3) I wouldn't have believed it was possible, and I was honestly very surprised and even a little scared that the engine started.
4) Then I'm glad that VW is improving.
5) It's amazing what you're willing to believe is true - simply amazing.

Good evening.
Andi

PS: That's it for me now, I'm out of here .

Quote:

Someone modified my post yesterday at 8:32 PM.

Probably the spell checker. Generally, nothing is changed in the content, unless it involves things like illegal activities, which was not the case here.

Consequently, the "content" could not have "come across" any "differently."

Quote:

It came across as a bit more "intense" than what I had written.

That is false.

Edit: And anyone who continues to lie, especially by making false accusations, will be banned and will not be allowed back.