CAN speed

Hello,

Can someone tell me what speed the CAN bus operates at in an Audi A4 radio?
Is this an Audi A4 (model 8E) from the year 2002?

Thank you.
Alex.

Hi Alex,

The comfort CAN operates at a speed of 100 kbit.

Best regards.
Maxx.

In the A4 B6, that should be the infotainment CAN bus on the radio, but it also runs at 100 kbps.

Hello,

Okay, thanks. I'm now able to get on the bus and log in.
If I want to send a command like, for example, '0x5C1 D:1 Data: 2B' to set the mute function, do I need to send it multiple times consecutively? Nothing happens after sending it just once.

Is '5C1 1 2B' the mute message from the multifunction steering wheel? If so, do you have an MFL (multifunction steering wheel)? If not, have you told the RNS-E (configured it) to think that an MFL is connected?

'The values I mentioned in my previous post are for a Passat B6. I don't believe they will be the same for an Audi. If you have a multifunction steering wheel, you need to log the information when you press a button and then identify the ID and corresponding values that are being sent. The easiest way to do this is to open the log file in Excel and sort by ID to find the IDs that appear only a few times.'

Stig.

In the A4 B7 that I once owned, the MFL messages were displayed on code 5C3. But as far as I know, there isn't a mute button on the MFL in either the B6 or the B7 models, right?

Hello,
No, I don't have an MFL; that's the reason why I'm doing this. I want to build it myself.
I've coded the navigation system to 0301317, so it should have MFL functionality.
'Nothing happens when I send it just once; I'll try sending it more frequently.'
Unfortunately, I can't log that because I don't have an MFL.
'If I write to ID 0x261, I can see the text in the FIS (Flexible Diagnostic Interface). It gets overwritten by the radio after about 200 milliseconds, but that's not a problem; it's fine if I have to resend the message every 50 milliseconds. This is just to verify that my hardware is working correctly.'

Hi Alex,

It's possible that the command alone might not be sufficient, and you may need to first inform the navigation system that you are present (by initializing it via CAN).
As long as you don't do that, no messages will be accepted, and it usually involves bidirectional communication, meaning not just sending commands but also receiving 'alive' signals, etc.

Unfortunately, I can't give you specific information about the Audi because I drive a VW.

Sure, here is the translation of the text from German to English:

'Cu' is a Spanish word that means 'with'. It can be used in a variety of contexts, such as:

* To express agreement or support: 'Estoy cu contigo.' (I am with you.)
* To indicate possession: 'Tengo un coche cu cuatro puertas.' (I have a car with four doors.)
* To describe a relationship: 'Soy amigo cu él.' (I am friends with him.)

In some cases, 'cu' can also be used to mean 'and'. For example, you might say 'Voy al cine cu mis amigos.' (I'm going to the movies with my friends.)

Hello,

That might be the case, or at least something along those lines.
I have now coded my RNS-E to the following MFL code: 0301317.
And then I immediately get the following error message in the navigation system:
00466 - Control module for steering column electronics (J527).
008 - Implausible Signal
The steering column control unit should normally process the Multifunction Leather (MFL) buttons and send corresponding messages. However, since the module neither has any buttons itself nor is it configured for MFL functionality and cannot be configured as such, the signal in the form of a CAN message will likely be missing.

I was browsing through some logs and found the following on my bus:
Message | Length | Data | Period | Count | Description
223h 3 00:08:00 50 6
261h 8 20 20 20 20 20 20 20 20 800 235 first line: FIS
263h 8 20 20 20 20 20 20 20 20 800 235 second line: FIS
271h 1 10 100 1795 Ignition
351h 8 45:00:00.000000 75 7B 10 100 1795 Speed
353h 6 0F C0 0D 8D 7B 16 100 1795
428h 6 16 11 00 00 00 00 100 1876
436h 6 08 31 00 00 00 00 100 1874
461h 6 37 70 00 00 00 00 1
604h 8 80 00 00 00 00 00 00 00 1000 188
621h 3 00 EF 7B 100 1795 Door
623h 8 01 17 17 34 14 01 20 07 1000 181
627h 8 04 28 28 28 28 28 28 28 500 365
635h 3 00:00:08 200 898
651h 6 C0 14 61 20 18 40 500 360
653h 3 00:01:24 500 360
65Fh 8 00 09 77 DA 71 57 41 55 1000 29 VIN
661h 8 80 01 12 A0 00 00 00 00 1000 188 Radio Navigation Mode
6C0h 1 A3 1000 165
6C1 2 A1 0F 1000 168

It was a complete log, from inserting the key to the end of the after-run sequence.

Can anyone tell me on which ID the steering column control unit transmits data?
And what data is transmitted with each key press?

The question is, does my vehicle already have the steering control unit installed? If not, it would be easy to emulate. If it is already present, how can I 'block' it and send a new message? This could likely be done with a microcontroller that has two CAN interfaces on-chip. The idea would be to simply forward all messages and then modify one of them before sending it further .

What's most important to me is a log of an A4 printer with MFL functionality, and a key that explains what each button does.

Sure, no problem. Here's the translation:

'Thank you in advance.'
Alex.

Please try sending the following to the RNS-E:

5C3 2 39 02 previous track/station/song
5C3 2 39 03 next track/station/song

Hey, this also works without an 'alive' message;-)

Radio:

5c3 2 39 01: No function.
5c3 2 39 02 sender return
5c3 2 39 03 sender vor
Searching...
Search in progress, reverting.
5c3 2 39 06 loud
5c3 2 39 07 quiet
Searching...
5c3 2 39 09: not working.
5c3 2 39 0a: not working.
5c3 2 39 2b: not working.

MP3:


5c3 2 39 01: No function.
5c3 2 39 02 track back
5c3 2 39 03 track forward.
5c3 2 39 04: No function.
5c3 2 39 05: not working.
5c3 2 39 06 loud
5c3 2 39 07 quiet
5c3 2 39 08 fast forward
5c3 2 39 09: not working.
5c3 2 39 0a: not working.
5c3 2 39 2b: not working.

Do you also have the other function keys, like the mute button?
or do I just have to try all the data points?

My idea would be to recode the steering column control unit to use Multifunction Lever (MFL) functionality and then see what happens on the CAN bus.

But that actually works really well.

There's no mute button in Audi cars, at least not one that I know of.

Here are a few more to try out:

5C3 2 39 00 none
5C3 2 39 02 Previous
5C3 2 39 03 Next
5C3 2 39 04 Scan Up
5C3 2 39 05 Scan down
5C3 2 39 06 Volume+
5C3 2 39 07 Volume -
5C3 2 3C 2A Phone button pressed.
5C3 2 3C 00 Phone button released, changes to 39 00 after about a second.
5C3 2 3A 1C Mode button pressed.
5C3 2 3A 00 Mode button released, changes to 39 00 after about a second.
5C3 2 39 01 Mode button pressed before it returns to 39 00.
5C3 2 3A 1A Up/down button pressed within 2 seconds after pressing the Mode button.
5C3 2 3A 02 up
within 2 seconds after pressing the Mode button.
5C3 2 3A 03 down within 2 seconds after pressing Mode.
5C3 2 3B A7 vol up/down pressed
5C3 2 3C 07 vol down after pressing phone button
5C3 2 3C 06 vol up after pressing phone button.

Okay, while we're on the subject, I'm looking for the messages related to switching the FIS (multi-function display). Specifically, the ones that are sent from the steering column control unit to the instrument cluster for FIS up/down/reset functions. My test steering column control unit isn't yet coded for the FIS, and it seems you can't reprogram it without a comfort control module. Also, I haven't connected the comfort CAN bus in the car. So, if anyone has anything related to this, please let me know.

Hello,

Where did you get all those IDs and the data associated with them? It's not that easy to obtain them through logging .

I wanted to send you the FIS up/down/reset logging data, but unfortunately, nothing happens on the CAN bus related to the radio when I interact with the lever for the onboard computer. Is that a different bus?

Alex.

Sure, just log the data. I once borrowed a B7. So, you remove the radio, put an adapter connector in between, and log everything you can. But that was only the infotainment CAN bus. The steering wheel controls communicate directly with the steering column control module, which then communicates with the instrument cluster via the comfort CAN bus and the drive CAN bus. But as I said, I don't have a connector on the comfort CAN bus yet so I can't just plug in my CAN USB adapter.

Hello,

nachdem ich nun mein MFL fast fertig habe noch zwei Fragen.
Is the 5C3 2 39 00 message transmitted cyclically? If so, is it sent every 200 milliseconds or something similar?

Regarding the 'Mode' setting in Prev/Nex, it currently sends '3A 1A' along with '3A02' and '3A03' for the wheels. Is '3A 1A' being sent *instead of* or *in addition to* '3A 02' or '3A 03'?

I have now installed a Mega8 in my steering wheel that communicates with a Mega32CAN. The CAN messages are arriving as I expect, and I will be testing it in the car next week .

Sure, here's the translation:

'Thank you in advance.'
_Alex