Golf 4 CAN Connector: Find it here!

Hello,

I now have an "Automotive Interface (CAN adapter)". It comes with software for logging data from a CAN bus. I would like to connect it to one of the CAN buses in my vehicle. I am particularly interested in connecting it to the engine CAN bus and the one where ABS and ESP are connected (including sensors like the yaw rate sensor).

Where and on which pins can I find the corresponding lines (CAN-HIGH, CAN-LOW)?

Do I need to know any other settings besides the baud rate (500 kbit/s?) for my adapter to be able to read the data? (With RS232, there were things like handshake, parity, bits, and stop bits...)

Vehicle: Volkswagen Golf IV Variant 1.9 TDI, manufactured in October 2002, engine code AXR.

Regards,
Christian.

Chr_Meissner wrote:

Where and on which pins can I find the corresponding lines (CAN-HIGH, CAN-LOW)?

The CAN system of the AXR may not be fully wired in all cases. The two existing CAN bus systems are combined via a CAN gateway located in the instrument cluster. The outputs from the CAN gateway can be found on the diagnostic connector.

14 - CAN-L
6 - CAN-H

Otherwise, you can find all the CAN signals on the green 32-pin connector at the control unit (KI).

8 - CAN-H - Comfort CAN (central locking/alarm system)
9 - CAN-L - Comfort CAN.

19 - CAN-H - Motor + Sicherheits CAN (Airbag, ABS/ESP, M-STG, autom. Transmission.
20 - CAN-L - Motor + Safety CAN.

Since the AXR engine was not available with an automatic transmission, the CAN control unit for it is therefore unnecessary.

Thank you for the quick response; I'll give that a try.

Under http://homepages.vype.de/batluckies/Golf_III/Meine_Projekte/Tacho_G_IV_in_G_III/1h_g4t.htm, instead of pin 8/9 for CAN, pin 27/28 is used on the green 32-pin connector of the instrument cluster in the Golf IV. I will check both variants, maybe there are several types...

As far as I know, I don't have a CAN interface (KI), since I don't have a Multifunction Display (MFA). Also, I haven't been able to detect any CAN signal at the terminals of the diagnostic connector for some time. This explains why there is no CAN gateway.

Regards,
Christian.

Chr_Meissner wrote:

... As far as I know, I don't have a CAN interface (KI), since I don't have a Multifunction Steering Wheel (MFA). Also, I haven't been able to detect any CAN signal at the terminals of the diagnostic connector for some time. This explains why (there is no CAN gateway).

So, starting in May 1999, all KIs (control units) installed in the G4 normally have a CAN gateway.
Whether or not MFA is enabled.

Quote:

Instead of pin 8/9, pin 27/28 is also used for CAN on the green 32-pin connector of the instrument cluster in the Golf IV.http://homepages.vype.de/batluckies/Golf_III/Meine_Projekte/Tacho_G_IV_in_G_III/1h_g4t.htm Okay. You can more easily connect to this port at the diagnostic connector (14 + 6). You don't need to remove the instrument cluster for this

.

By the way:
The pin configuration described there is for vehicles from May 1999 to April 2001. These are vehicles with a CAN bus system (only the engine CAN). From May 2001 onwards (which includes yours), there is a second CAN bus in the G4, called the Comfort CAN. This also uses the connections I specified and runs through the instrument cluster.

If you connect your interface to the CAN bus at the diagnostic connector, you won't receive any CAN traffic. Theoretically, it might be possible to establish a diagnostic session there, but on the Golf IV, diagnostics, chip tuning, and other flashing processes still work entirely through the K-line. I would say with 99.9% certainty that even in workshops, the diagnostic CAN bus at the OBD connector is not used. So, for now, forget about the OBD connector.

You can listen to data on the Motor-CAN (500 kbit/s) and Comfort-CAN (100 kbit/s). Simply connect and the data will appear. However, since you don't seem to have any experience with CAN yet, I strongly suggest that you start with the Comfort-CAN and gain some experience there first.

Here are some examples of the data you can obtain from the CAN bus regarding comfort features: ignition status, speed, engine RPM, window/door/central locking status, climate control, digital signal processing (DSP), mirrors, lights, buttons from the multi-function display (MFA) and multifunction steering wheel (MFL), time, etc.

Have fun!
Axel.

To the best of my knowledge, there were also some Golf 4 models that could only be diagnosed via CAN bus; am I mistaken about that?

We once installed a cruise control system in a Volkswagen Golf 4 Variant from November 2004 (1.6 gasoline engine, BCB), but we were unable to activate it (we could read the error codes).
The VW workshop responded by saying that they would communicate this through other channels.

michiglaser wrote:

To my knowledge, there were also Golf 4 models that could only be diagnosed via CAN bus, or am I mistaken?

I would very likely rule out the possibility that they are *only* diagnosable via CAN bus.

michiglaser wrote:

We once installed a cruise control system in a Golf 4 Variant from 11/2004 (1.6 gasoline engine, BCB), but we were unable to activate it (we could not read the error codes). The VW workshop responded with the comment that this would be communicated through other channels.

It's certainly possible that individual control units of a newer type can perform diagnostics via the CAN bus.
Okay, I just did a quick Google search. It seems that the part number 1J0-907-487A is no longer able to be coded via K-Line. (The "B" version still can.)

I once installed an RNS2 (from a Touareg) in my Golf IV. The RNS2 also didn't have a K-line anymore. However, I was still able to code it using VAG-COM via the K-line. In this case, the instrument cluster took over the gateway function and 'routed' the diagnostics from the K-line further through the comfort CAN. Perhaps it's also a matter of the VAG-Com version.

Greetings,
Axel.

axmax wrote:

If you connect your interface to the CAN bus at the diagnostic connector, you will not receive any CAN traffic. ...

Okay.
This CAN connector needs to be properly configured to function as an interface.

Thank you for the tips.

I have now expanded the AI (instrument cluster) and would like to solder a small cable to the corresponding "terminals" to bring the CAN bus to the outside. Ideally, where the connector is soldered. Unfortunately, I can't remove the needles from the AI, so I can't access the back of the circuit board either. Is there a trick for that?

(The other way to access the wiring, which would involve cutting the cable, is not possible right now because I don't have the necessary components for that.)

Best regards, Christian.

PS: I'm really looking forward to seeing the first CAN data...

Chr_Meissner wrote:

Unfortunately, I can't remove the probes from the AI unit, which prevents me from accessing the back of the circuit board. Is there a trick to do this?

Using a thin flathead screwdriver, you can get under the hand and then apply pressure against the white plastic to pry it out.

You're welcome. It worked.
I was just afraid of breaking the (servo) motor in the process.

GREAT! Now I'm receiving data!

"No data was received on the Comfort-CAN bus. Then I connected to the Engine/Safety-CAN bus – and there's quite a lot of activity there... (with some messages being sent every 0.25 milliseconds)."

I only read the CAN data . Since then, my airbag light has been on! Is it now deactivated? Could this be because I disconnected the instrument cluster? ...?

Best regards, Christian.

Chr_Meissner wrote:

I only read the CAN data. Since then, my airbag light has been on! Is it now deactivated? Could this be because I disconnected the instrument cluster? ...?

"Hey. You didn't disconnect the battery, did you? It could also be due to the "read-only" mode. I used to experience that more often with my Golf 4. The airbag control unit seems particularly sensitive."

But I have to say it again... the MotorCAN is not a toy! Something should be connected to your ComfortCAN. What is the part number of your instrument cluster?

Hello,

"I didn't disconnect the battery, just the connectors from the instrument cluster. I don't know the part number of the instrument cluster yet; I need to connect VAG-COM (probably tomorrow). As far as I know so far: it's from a Golf 4 with a 74 kW TDI engine, manufactured in October 2002, and without MFA (Multi Function Display)."

Quote:

But I have to say it again... the MotorCAN is not a playground!

I would like to use the Comfort-CAN for practice, but what if it doesn't work? I have tapped into terminals 8 and 9 for that purpose, without a ground connection. What is the worst thing that could happen if I only read data? (I certainly don't want an airbag exploding in my face.)

So far, I have identified the following IDs: 16, 17, 80, 194, 416, 640, 648, 800, 896, 906, 1056, 1152, 1160, 1184, 1192, 1312, 1408, 1416, 1440, 1488, and 1496. Is there a list available that explains the meaning of these IDs and their corresponding data formats?

Best regards, Christian.

Chr_Meissner wrote:

I would like to use the Comfort-CAN for practice, but what if it doesn't work? I have connected terminals 8 and 9 for that purpose, without a ground connection. What is the worst thing that could happen if I am only reading data? (I certainly don't want an airbag exploding near my face.)

Well, if you have a CAN interface connected, it's easy to accidentally write something. But that probably also depends on the software being used.

Chr_Meissner wrote:

So far, I have found the following IDs: 16, 17, 80, 194, 416, 640, 648, 800, 896, 906, 1056, 1152, 1160, 1184, 1192, 1312, 1408, 1416, 1440, 1488, 1496. Is there a list somewhere that contains their meanings and data formats?

No, there isn't. Debugging and reverse engineering are needed. Take a look at http://www.canhack.de, as there are some more tips and some IDs are explained there.

Regards,
Axel.

Is there any interest in corresponding hardware and software? I am certainly interested in the topic; it's likely a wonderful toy for current cars.

From what I've read, there are no ready-made circuit boards available anywhere, but they could be manufactured relatively quickly.

Best regards, Rainer.