CAN-BUS Car mediacenter

Project MPi3 – Display additional Data

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With a controller connected to my Vehicles CAN-bus, I don’t want to limit the use of it to song-title and music controls. So I started to look for some more interesting values to get from the bus.
Sadly the “MS-CAN” (entertainment bus), which I am connected to cause of the info display, doesn’t allow communication to the ECU (also, this factprevents me from messing with the engine or other critical components).

The components connected to the bus do have some interresting informations and GM built a diagnostic protocol that lets you ask the controller for the actual values. This leads to the folling data:

248 # 06 AA 01 01 07 10 11 - Ask the A/C controller (0x0248) for measuringblocks 01, 07, 10 and 11
548 # 01 03 A5 00 00 01 9C 00 - 01: 0x03A5: Solar sensor: 4.665V - 0x019C: Indoor temp sensor: 2.06V
548 # 07 00 90 04 3D FE 70 00 - 07: 0x90: Voltage: 14.4V
548 # 10 00 91 02 B2 03 1E 96 - 10: 0x0091: Out-temp: 14.5°C - 0x02B2: Engine temp: 69.0°C
548 # 11 08 ED 00 30 01 FE 23 - 11: 0x08ED: RPM: 2285 - 0x30: Speed: 48 km/h - 0x23: LED: 35%

The described values are only the ones that I already figured out.

My software now listens for this data on the bus and writes the values on the display.

  • IMG_20150927_123647

The displaymode can be switched with the number keys on the headunit (which are also unused in aux mode)


Next: New housing and published all souce code

11 replies on “Project MPi3 – Display additional Data”

Hello Trueffelwurm,

I’ve just read your fantastic post recently and based on your work I’ve managed to display the engine coolant temperature to the GID display for my Astra H. My only problem is that I want the data to be displayed on the BC screen, not on the Audio screen (which is totally reasonable in your project). Did you do researches finding the other screens as well? I found that 0x03 is the main Audio screen, did you try all the values from 0x01 to 0xff? I just want to measure my chances finding the best screen for my case. 🙂

Thanks for all your efforts!

Hi, as far as I know, there is no way to inject text in the BC-Screen.
What you could do ist to send your cooland temperature as the set A/C temperature (0x0A26), so it will be displayed in the lower left corner of the display.


finally I used the Phone screen (0x6c8)) but I was able to write to the BC screen, too (only it was ugly). I think we could exchange some knowledge, 🙂 There is only one thing I’m especially looking for, is querying the current volume. I couldn’t find this anywhere. If you have a little free time I’d be glad if you could send me an email. Thanks!

Hello jens, is it possible to obtain the Range, instant and average consumption from the display?
My plan is to use an aftermarket display and push the data in.

@six, could you please share the info on the CAN network for this car?

Sorry, 0x6c8 is the climate screen, 0x6c7 is the Phone screen

Hi six, jens,

Did you managed to get the range, instant and average consumption?
Also six, would you mind sharing your findings regarding the CAN bus?

Hello guys, did you managed to extract the data like range and instant and average consumption? I plan on replacing my display but still keep this information.

Six, could you please send the info that you have on the Astra CAN network?

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