CAN ID speed signal DSG transmission DQ250

Next problem.

Does anyone have an idea which ID the speed signal from the DSG transmission comes from?

The following IDs are possible:

0x38A (I believe bytes 1 and 3 represent the speed of the transmission shafts).
0x440
0x448
0x540 (Byte 7 = walking indicator).
0X548
0X570

I've already tried sniffing the traffic, but I haven't had any luck; it probably consists of just 2 bytes.

Attached are the IDs that are present on my bus; the ones mentioned above are those coming from the transmission.

Thank you very much.

Best regards, Marco.

Does the speed not come from the ESP/ABS system?

Hi there,

Okay, I've already found some information. However, it doesn't have ABS or ESP. But I read that there might be a replacement signal coming from the DSG transmission, but I don't know if that's true.

"I definitely see the current speed in the VCDS measuring blocks for the transmission. This works while driving and displays the current speed. Therefore, it's reasonable to assume that this information also comes out via CAN bus, but it might not be the case."


"In my case, that would be the only way to achieve the desired speed without having to modify anything. I also need this speed information for the engine control unit (ECU), but the ECU receives it via a separate cable and a square wave signal."

Hello,

The link I sent earlier was not relevant. I couldn't find any information about speed in the news articles from DSG.
But the selected gear is indicated in the data byte with CAN ID 0x440, specifically in the lower 4 bits of byte 2 (Com_stGear).

Based on this information and the engine speed, the engine control unit could estimate a substitute speed.

Best regards, Rainer.

Okay, with that, I could at least calculate the speed on the speedometer based on engine RPM and the current gear ratio. But whether it's accurate is another matter. As you mentioned, it's more of a guess than a precise calculation.

Are you sure there isn't any speed information included in the ID values for the transmission?

Hoerli wrote:

Are you sure there isn't any speed information included with the transmission IDs?

No, only death is certain. However, in the DSG transmission information I have, I haven't found any data regarding speed.

Okay.

Here's what else I found; see the image attached.

Something needs to be derived from this, possibly based on the initial speed (0x38A) and the gear ratio.

That would also be a more accurate calculation than one derived from the engine speed.

Here it states that the replacement signal comes from the ESP system and not the other way around. Consequently, while the signal will likely exist internally and be accessible during diagnostics, it won't be transmitted externally (this is my assumption).

Unfortunately, I no longer have the Golf 7 with the DQ250 transmission, otherwise I could have logged some data from it.

Please provide the text you would like me to translate from German to English. I will then give you only the translation, without any explanations.

unsigned char speedvorher = 0;
unsigned char speedtmp = 0;

text
if (canMsg.can_id == 0x320) {
text
speed = canMsg.data[4];
text
speedtmp = speed * 1.32;
Bitte gib mir den deutschen Text, den du übersetzt haben möchtest.

0x570 should be a combination (model), but it also works as is.


Please provide the text you would like me to translate from German to English. I will then give you only the translation, without any explanations.

Michael42 wrote:

.... unsigned char speedvorher = 0; unsigned char speedtmp = 0; text if (canMsg.can_id == 0x320) { text speed = canMsg.data[4]; text speedtmp = speed * 1.32; Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. 0x570 should be a combination (model), but it also works as is. .....

In his log, ID 0x320 does not appear at all, therefore it will be difficult to calculate anything with it...