Timpanogos Slim
08-08-2021, 12:38 AM
On audizine this seems to be the least wrong forum for this question.
I'd love suggestions for a better place to discuss it.
I have an Ultragauge-EM. It's like a scangauge in the sense that they're both configurable gauge displays that plug into OBD2.
I'm annoyed that it doesn't read boost pressure on my b8.5 S5 (or my old mk5 gti) and i would like it to read trans temperature as well, which is not a standard obd2 diagnostic.
For $10, the UG people will flash it with MX firmware, which allows the user to program up to 8 vendor-specific gauges.
Ultragauge seems to be pretty focused on fleet vehicles, which makes total sense. So the vendor-specific gauges they can pre-configure are mostly for full size trucks and delivery vans.
They (wink wink) mention that their label format for vendor gauges is the same as Scangauge's X-Gauge system.
The labels (or whatever they are called) for many audi vehicles are on this scangauge page:
https://www.scangauge.com/support/x-gauge-commands/audi/
All of them, for trans temp, seem to be txd "07E122A008" (command to request this UDS block?), rxf "C46205A03608" (Filter to recognize the response?), rxd "3008" (no idea), and mth "00090005FFD8" (pretty sure this is the math that has to be done to the response data in order to make it human-readable).
Pretty arcane stuff!
Clearly, this sort of thing is how the P3 digital gauge works. Frankly, it's how VCDS works too, though ross-tech has taken measures to obscure what goes on behind the scenes.
And then we come to the point where i'm not completely lost editing source code. I know my way around a soldering iron. I'm comfortable messing around with arduino shit.
There's example source code for canbus sniffers available online. I have a genuine hex+can vcds cable. I have various arduino boards and even a canbus interface board.
I'm not much of a coder or hacker but i know a few people who are.
It should be possible, even not very difficult, to suss out how to request trans temperature and manifold pressure via UDS (which goes over CAN) so that i can add these useful gauges to my ultragauge. It's not even reverse engineering, it's just peeking under the hood.
There isn't a lot of discussion online about how automotive canbus or uds really works.
Any thoughts? pointers?
I'd love suggestions for a better place to discuss it.
I have an Ultragauge-EM. It's like a scangauge in the sense that they're both configurable gauge displays that plug into OBD2.
I'm annoyed that it doesn't read boost pressure on my b8.5 S5 (or my old mk5 gti) and i would like it to read trans temperature as well, which is not a standard obd2 diagnostic.
For $10, the UG people will flash it with MX firmware, which allows the user to program up to 8 vendor-specific gauges.
Ultragauge seems to be pretty focused on fleet vehicles, which makes total sense. So the vendor-specific gauges they can pre-configure are mostly for full size trucks and delivery vans.
They (wink wink) mention that their label format for vendor gauges is the same as Scangauge's X-Gauge system.
The labels (or whatever they are called) for many audi vehicles are on this scangauge page:
https://www.scangauge.com/support/x-gauge-commands/audi/
All of them, for trans temp, seem to be txd "07E122A008" (command to request this UDS block?), rxf "C46205A03608" (Filter to recognize the response?), rxd "3008" (no idea), and mth "00090005FFD8" (pretty sure this is the math that has to be done to the response data in order to make it human-readable).
Pretty arcane stuff!
Clearly, this sort of thing is how the P3 digital gauge works. Frankly, it's how VCDS works too, though ross-tech has taken measures to obscure what goes on behind the scenes.
And then we come to the point where i'm not completely lost editing source code. I know my way around a soldering iron. I'm comfortable messing around with arduino shit.
There's example source code for canbus sniffers available online. I have a genuine hex+can vcds cable. I have various arduino boards and even a canbus interface board.
I'm not much of a coder or hacker but i know a few people who are.
It should be possible, even not very difficult, to suss out how to request trans temperature and manifold pressure via UDS (which goes over CAN) so that i can add these useful gauges to my ultragauge. It's not even reverse engineering, it's just peeking under the hood.
There isn't a lot of discussion online about how automotive canbus or uds really works.
Any thoughts? pointers?