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Snooky

Joined: 04/18/2010 Posts: 18 Karma: +5 / -0
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18-04-2010, 18:42 Subject: Would like to control an all-wheel drive system |
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I'm currently in the middle of an experimental conversion project where I'm planning to use an all-wheel-drive system from VW/Audi.
This drive system features a Haldex clutch on the rear axle, a compact mechatronic unit that is typically directly connected to the CAN bus.
The purpose of the communication would be to control the clutch's engagement level, ranging from 0-100%, and potentially to read its current status.
Has anyone here, by any chance, identified the ID and data frames within a running system, or has anyone already worked with such a drive system?
Sure, here's the translation:
"LG" translates to "Best regards" or "Sincerely" in English.
Snooky.
Translated on 03-07-2026, 15:19.
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p.ostrich Guest
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21-04-2010, 15:02 Subject: Subject: Want to control an all-wheel drive system |
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I don't think so, but maybe someone else will chime in.
What is the background of your work? 'Is this a term paper or something?'
Sure, here's the translation:
'lg' is a German abbreviation that stands for 'liebe Grüße,' which translates to 'best regards' or 'warm greetings' in English.
Translated on 03-07-2026, 15:19.
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Snooky

Joined: 04/18/2010 Posts: 18 Karma: +5 / -0
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18-05-2010, 20:56 Subject: Subject: Want to control an all-wheel drive system |
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It's purely for personal use and considered a hobby. The drive system will be installed in a modified, older vehicle that doesn't have CAN bus functionality, so it will also need to be controlled via a custom-built control unit. That's exactly the task I set for myself, and this is how far I've gotten so far...
I'm a complete beginner when it comes to CAN technology and could really use some help getting started. It would be great if someone with experience could offer some guidance.
I've been trying to find information, but it's been anything but easy.
The entire issue concerns the VW/Audi drive control unit, which operates at a data rate of 500 kbit/s. The Haldex unit, a multi-plate clutch with a mechatronic control unit, can only be controlled via CAN bus.
I have already assembled the device and equipped it with an OBD interface (connector) where I have connected the CAN and K-Line. The data reading using the VAG-COM diagnostic tool (shop.dieselschrauber.de) works perfectly. I was already able to read an initial data stream using the Tiny-Can I interface (with special firmware) and the can tool software.
As soon as the power supply is activated, Haldex periodically transmits the following data to the bus:
ID 2C0 / DLC 2 / Data 3880 / Period 10
As I could gather from some threads related to the Comfort CAN system, it's possible that the Haldex control unit is trying to communicate and is waiting for a response from another control unit.
I also know that the engine control unit (ECU) and the ABS control unit are normally part of this system. So, it's a trio: the Haldex system receives data from the two control units and processes it for its own use. This data includes wheel speeds of all four wheels, engine load, longitudinal acceleration, throttle position, etc. The Haldex oil temperature should also be readable, or is it transmitted cyclically?
Now, one would need to know these telegrams in order to simulate such a scenario and make the whole thing manageable.
As a first step, and I'm almost certain about this, we need to simulate the operation of the ABS and engine control unit (ECU), because when I read the error codes from the Haldex system, I always get error messages indicating that the communication between the ABS and the engine ECU is not working. So, what should the Telegrams from ABS and the motor control unit (STG) look like, and is this sending (presence notification) a continuous process, or is it only a one-time event when the STG is started, just to confirm that all the necessary participants are present?
For starters, I think this gives us both a general overview of the whole thing. Now it will get more technical and delve into the details  .
Ideally, it would be best to document a vehicle with this propulsion system and try to find and understand the necessary communication signals.
I hope someone has experience with this and can give me some advice.
I would be truly grateful for any help, and I'm sure I'll only find it in this interesting forum.
Regards,
Snooky.
Translated on 03-07-2026, 15:19.
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Maxx Guest
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19-05-2010, 23:16 Subject: Subject: Want to control an all-wheel drive system |
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The communication between Haldex, the engine, and the ABS must be constant.
I can imagine that this project will be very challenging and difficult to complete.
There's a lot of complexity involved in that.
I believe that logging the data from a 4 Motion system is a prerequisite.
Best regards,
Maxx.
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Snooky

Joined: 04/18/2010 Posts: 18 Karma: +5 / -0
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23-05-2010, 14:58 Subject: Subject: Want to control an all-wheel drive system |
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Do you mean the presence of measurement data or the presence of a ring response?
It might come to the point where I just give up and stop caring, but I'm not giving up that quickly. Right now, logging everything is probably the only option, unless someone else with more experience chimes in. 
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Maxx Guest
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24-05-2010, 22:15 Subject: Subject: Want to control an all-wheel drive system |
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I would have said that both pieces of data
Perhaps someone with experience will come forward.
Regards,
Maxx.
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Snooky

Joined: 04/18/2010 Posts: 18 Karma: +5 / -0
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05-06-2010, 17:35 Subject: Subject: Want to control an all-wheel drive system |
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I will soon have the opportunity to participate in an A3 Quattro event, and I believe the following signals are important for my participation:
From ABS:
Speed sensors for all 4 wheels.
Longitudinal acceleration sensor.
Foot brake.
Parking brake.
From the engine:
Engine speed.
Last or. Engine torque.
Accelerator pedal position.
I have a big request.
If anyone is familiar with the Telegram messages containing the sensor data mentioned above, would they be so kind as to share them with me?
That would greatly help with the search; I'll probably be overwhelmed by a huge amount of data as soon as the ignition is turned on  .
Regards,
Snooky.
Translated on 03-07-2026, 15:19.
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Master_M Guest
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29-08-2010, 15:53 Subject: Subject: Want to control an all-wheel drive system |
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Hello fighters,
It's great to know there are still more people with hope.
We're dealing with the same issue here, only it's about torque distribution.
in a Golf VI R, which is also supposed to have Haldex (which I think).
(will be structurally similar to yours)
Procedure:
1.) To log data, connect to the correct CAN bus (some CAN lines are 'censored').
and you won't find all the data on it) - so it's best to connect it directly to a...
Haldex installation... you can find a great guide with pin assignments here ->
<!-- m --><a class='postlink' href='http://www.tt-eifel.de/index.php?fehler_haldex'></a>
2.) Log all data, filter it, and analyze it.
3.) Disconnect the Haldex system from the vehicle's CAN bus and control it with its own CPU, ideally.
with a small, freely programmable microprocessor.
'For hobbyists, something like a CC2-Control from Conrad Electronics might suffice, although it's not specifically designed for...'
Originally designed for the automotive industry, but with the software, it costs only about 100 euros.
and that's perfectly sufficient!
Our project is also still in its early stages, and our experience with CAN technology is limited to a single instance.
a few preliminary projects with other car brands...
Good luck!<!-- m -->http://www.tt-eifel.de/index.php?fehler_haldex{MARKER}{MARKER}
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p.ostrich Guest
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30-08-2010, 9:51 Subject: Subject: Want to control an all-wheel drive system |
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Hi.
Can I ask another (silly/basic) question?
Why do you want to do that? What is the background or reasoning behind it? It seems the Haldex system isn't working well enough for you, or that you expect it to function differently.
Best regards.
Translated on 03-07-2026, 15:19.
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Snooky

Joined: 04/18/2010 Posts: 18 Karma: +5 / -0
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09-10-2010, 22:13 Subject: Subject: Want to control an all-wheel drive system |
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@Master_M
Yes, I had the same thoughts. Thank you for the information.
Unfortunately, I had to take a break, but I recently had the can tool logged on a 4Motion vehicle.
I built an adapter with a CAN bus tap and connected it directly to the Haldex unit, which provides a direct access point without affecting the rest of the system.
Now I just need to understand, search, and then test.
I think your Haldex version will work in a slightly more complex way; they are certainly not built the same, but it's good that you are also dealing with it  .
@p.ostrich
Okay, it's not doing what it's supposed to. In my case, it can't even do that, because it doesn't work as a standalone application.
However, in the vehicles where she normally works, she is sluggish and only functions properly during a few maneuvers.
I want the Haldex system to be used more effectively and to do exactly what I want it to do, so the only option is to build something myself.
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shift Guest
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14-06-2011, 21:06 Subject: How's it going? |
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What's the current status here?
Did you achieve anything?
drive a Haldex without CAN bus, and with would be better 
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Master_M Guest
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04-09-2011, 17:52 Subject: Subject: Want to control an all-wheel drive system |
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Hello Haldex enthusiasts,
Are there any new developments, or have there been any initial successes yet?
I still dream of a 'Haldex on/off' switch...
Best regards,
Translated on 03-07-2026, 15:19.
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Gti2004
Joined: 01/03/2019 Posts: 7 Karma: +0 / -0
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03-01-2019, 16:54 Subject: Would like to control an all-wheel drive system |
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I was wondering if you managed to get the Haldex CAN bus working.
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