C5 (X7) CAN BUS informations

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Bury
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Joined: 11 Dec 2023, 21:36

C5 (X7) CAN BUS informations

Post by Bury »

Hello everyone!
This is my first post and I hope my question won't be trivial ;)

I have a C5 X7 V6 HDi (2012).

I need information about the CAN bus (or other).
What CAN speeds are in the car? I know from experience that 500kbps has IDs such as the mechanical parameters of the car.
Are there other CAN bus speeds? I care about multimedia buttons, steering wheel buttons, etc.
Is there a different bus intended for "comfort management" of the car?

I need this information to create a small BT music receiver connected to AUX (NG4) and the CAN bus. This way I could control the music from my phone using the buttons in the car and the steering wheel.

You can see IDs in the videos. However, I was unable to identify the IDs of the multimedia buttons I was interested in. IDs are not reported on the CAN bus :/



Thank you for your help!
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GiveMeABreak
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Re: C5 (X7) CAN BUS informations

Post by GiveMeABreak »

This isn't something I am aware the NG4 can do with any AUX input. On all PSA vehicles with AUX, the control is from the device only, with only the volume being controllable from the vehicle.
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Marc
Bury
Posts: 4
Joined: 11 Dec 2023, 21:36

Re: C5 (X7) CAN BUS informations

Post by Bury »

Indeed!
NG4 does not have the function of receiving music via Bluetooth and control music using buttons. This is the problem I want to solve.
My idea is this:
I built a module based on ESP32 that has Bluetooth. With libraries like this I can stream music to the ESP32 and the ESP32 can use AVRC commands to control the phone's music player (just like wireless headphones).

ESP32 can transmit audio from Bluetooth to the audio output.
ESP32 also has a CAN controller. With libraries like this you can read, send and react to any messages from the CAN bus.

With such possibilities, you only need to write a few lines of code to control music from your phone using the buttons on the steering wheel.
The only problem is to respond to the correct message sent by the buttons in the car with a specific ID.

To find out which button has what ID and data, I have to use reverse engineering and try to correlate events of buttons with ID. For this I need the speed of the CAN bus to be able to see less priority IDs such as buttons etc. With higher priority (CAN bus speed is 500kbps), various car parameters are available, starting from headlights ending with the engine, etc.

A small example in the video of what "decoding" IDs looks like and how they work.

Why not use a BT receiver connected to AUX? I actually have one and it works fine, but I miss controlling the music player on my phone using the buttons on the steering wheel and the phone call function.
I wouldn't like to disfigure the car's dashboard with Chinese fancy Android radio with displays like a TV ;)
wheeler
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Re: C5 (X7) CAN BUS informations

Post by wheeler »

Bury wrote: 24 Jan 2024, 23:12
What CAN speeds are in the car? I know from experience that 500kbps has IDs such as the mechanical parameters of the car.
Are there other CAN bus speeds? I care about multimedia buttons, steering wheel buttons, etc.
Is there a different bus intended for "comfort management" of the car?
I/S High speed CAN 500 kbps
Body Low speed CAN 125 kbps
Comfort Low speed CAN 125 kbps
Diag CAN 500 kbps
LIN 19.2 kbps
There is also a K line for diagnostics which is 10.4 kbps

The steering controls are connected to the comms unit by LIN connection which is then connected to the BSI via the Body LS CAN.
Bury
Posts: 4
Joined: 11 Dec 2023, 21:36

Re: C5 (X7) CAN BUS informations

Post by Bury »

Thank you very much for your answer!
Your information is very helpful!
In the meantime, I was also looking for important information.
Interesting, because I also tried to set 125kbps in the sniffer, but I didn't receive any data :/ It's possible that there is an error somewhere in the libraries. Tomorrow I will try different software settings. By the way, I understand that CAN 500kbps and 125kbps are on the same bus? I connect to the OBD2 connector on pins 6 and 14. Pins 3 and 8 are for "CAN - diagnostics"?
wheeler
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Re: C5 (X7) CAN BUS informations

Post by wheeler »

Full disclosure. I can test & scope CAN wiring & know what I should see but what actually goes along the lines is way over my head. The info I provided came directly from the C5 X7 multiplex dealer training manual so should be correct.
As far as i know the intersystems CAN, Body low CAN & Comfort low CAN are separate networks. They at least have different outlets from the BSI anyway.
Bury
Posts: 4
Joined: 11 Dec 2023, 21:36

Re: C5 (X7) CAN BUS informations

Post by Bury »

Hi!
Just yesterday I had access to my car and read the information in CAN 125kbps ;)
In OBD2 connector are no CAN 125kbps pins, so I connected to the FAKRA connector of the NG4 radio (pin 10 and 13). Now I'm starting to decode the IDs. I need it to start writing code for the ESP32.
If anyone is interested in details and a list of decoded IDs, I will be happy to help! When I finish the project, I will post information here.
Thank you for your invaluable help!
Here is a small sample (ID description in Polish, later will be in English):
Attachments
sesja125.jpg
dekodowaneID.png