Activating the Peugeot 308 Park Assist function

Hello everyone!
My 2020 Peugeot 308 has a well-functioning (and expensive!) parking assist feature. The problem: To activate them, you need to do the following: On the screen...
1. Select the "Driving" menu.
2. Select "Vehicle" function.
3. Select "Park Assist" function.
4. Select the "Parallel parking" function.
Then you can start with the parking maneuver.
It's impractical, too complicated, and too distracting for use in heavy city traffic.
The 2014 308 had an extra button that directly led to point 4.
My project is as follows: I want to intercept the commands on the diagnostic CAN bus that initiate the parking function and then, using appropriate hardware and software, send those commands sequentially to the bus myself. That means that a single button press handles points 1 through 4.

My questions about this:
1. How can I determine whether the diagnostic CAN connector uses the CAN or VAN protocol for pins 3 and 8? I only have a single-channel oscilloscope, so I'm assuming that there is practically zero voltage difference between the two channels in a CAN bus system.
2. Can you intercept and filter all standard messages using the software and hardware available for purchase here, and only save messages that are sent with a single keystroke, to be sent again later?

I assume that it will only work if it's CAN. It's too difficult with VAN.

Maybe someone can help me with this, that would be great.
Best regards, and thank you in advance!
Citrofan.

Good evening, Citrofan.


to question 1:

VAN and ABUS protocols never gained widespread adoption. CAN has become the dominant standard, replacing older variants.

So, you only need to process CAN messages.

If no communication is taking place on the CAN bus, there will be no voltage present. As soon as communication begins, you can either measure the differential voltage across the CAN bus or perform a voltage measurement against ground. A signal waveform and the communication speed can also be displayed using a single-channel device. To properly represent communication, it should ideally be a two-channel device.

If the oscilloscope is a bit more advanced, it can also decode the CAN bus.

Regarding question 2:

The CAN-BUS interface kit (from Dieselschrauber) will definitely be a great help with your project. You can trace the CAN-BUS, filter and analyze your IDs. And it is also possible to send messages back.

A checksum is not calculated for you by this tool, however.



On pins 3 and 8, you won't be able to read much data unless you put your parking assist control unit into diagnostic mode.

The IDs you desire are definitely running on the Comfortbus, which integrates your parking assist system, radio, and information display.

Attached, I've included a picture of the vehicle's body control module, and I've marked the connectors that are of interest to you. Here you will find the different CAN bus lines.

If you're unlucky, the only wires left in your car will be white. Then, verschandeln fingers and a magnifying glass are helpful to better read the small, printed numbers.

Does that help you for now?

Best regards,

Hello Ich_Can_nix.
Thank you very much for the interesting and detailed answer! Great, even with a photo! You seem to know a lot about PSA products!

My 308 still has colored wires, and I think the twisted orange and/or yellow wires are the ones to tap into.

It seems that the messages I'm interested in aren't appearing on the OBD connector, neither on the CAN bus nor on the BSI pins. Since the car is still under warranty, I'm hesitant to tap into any wires. Someone in another forum advised me to stay away from it... Of course, you could use fine needles to pierce the insulation, but... well. Could false commands potentially be used to disable or destroy very expensive components?

Regardless, the project appeals to me. You could perhaps use a similar trick to set the heating temperature using a rotary encoder instead of going through the menu steps. (It's a gift for my wife, and she would think it's great ).

I'm thinking about how to proceed.
Thank you again! Best regards, Citrofan.

Good day!
In the meantime, I acquired a 2-channel PC oscilloscope and tried to locate the Comfort bus. Unfortunately, I was unsuccessful. I did find a high-speed bus, but I'm not sure what kind it is. Perhaps someone knows the answer.
Even if I knew how to remove the connectors from the support without breaking them, that would also be helpful.
The connectors are wired differently in my 308 (colors, positions).
Attached are a screenshot and a picture of the connectors.
I would really appreciate it if a professional could give me some advice on how to proceed. Thank you in advance!

Hello,

Are there wiring diagrams available for purchase for Citroen cars, similar to those offered for VAG brands? These diagrams, tailored to your specific car model, can greatly simplify the identification of components and their functions. And, at least with VAG, they are reasonably priced. Edit:

servicebox psa wrote:

Technical Documentation: • 1-hour subscription: €7.50 (excluding VAT). VAT

The bitrate can be an indicator of the type of CAN bus. I only know of CAN-bus systems for vehicles that use 500 kbit/s. Comfort systems are usually slower, at 100 kbit/s. Of course, this may be different with PSA vehicles, but I have no experience with those. ECUs typically broadcast standard IDs on the CAN bus. If you have information about comparable vehicles, I would suggest searching for those specific IDs.
Or, you can simply check the wiring diagram.

https://public.servicebox-parts.com

Best regards, Rainer.

Hello Citrofan,

The green cable could be the power bus. Unfortunately, I can't say for sure.

The problem is that in the wiring diagrams, the color of the cable is not always the determining factor, but rather the label on the cable.

You can proceed with the cable identification using the alphanumeric code (5 digits).


Wiring diagrams can be found in the service manual provided by Peugeot.

https://public.servicebox-parts.com/pages/index.jsp


However, they are not shy when it comes to their pricing policy.
I'm not sure if access is available on an hourly basis. You should really do some research on that.

A call to the technical support hotline will be charged at €65.

If you're completely stuck and can't make any progress, I need to know exactly which vehicle we're talking about.


Best regards,

Michael.

Posted almost the same thing. It seems to be affordable, though.

Hello Rainer,

Okay.

I could have sworn that something else was there just a few minutes ago .


Best regards,

Michael.

Does it also ?

Hello everyone!
Thank you very much for your replies! That's simply amazing!
Regarding wiring diagrams: As a private individual, I can't register for the service portal, I just tried. So, I have to try to convince my dealer, but he has always been uncooperative in the past, and I don't want to risk the warranty (the vehicle is only 1 year old). I know from my experience with Citroen that it is strictly forbidden for dealers to pass on such documents.
I also posted it on Peugeot-Talk.de, and I'll check some French forums as well.
Sure, I will describe the results here as well, if I make further progress.
Thank you again, and best regards.
Citrofan (Yule)

Good evening.

I have access. If you just want to know where each CAN bus is located and what its designation/color is, I can gladly look that up for you.

I need the complete financial information for that.

Best regards,

Michael.

Good morning.

I took a quick look.

Okay, so we have a high-speed CAN.

The green wire comes from PIN 14 of the OBD CAN High bus (cable 9065) and connects to the distribution connector (see your image). From there, it continues as the purple wire (9065B) to the BNS (Body Control Module).

Analog: The pink wire with pin 6 connected to Low (cable 9604) will become orange wire 9604B.


The rest will follow later...

Waved.

Hello,

On your parking assist system, you will find two wires labeled 9034 (CAN Low) and 9035 (CAN High). These lead to the BSI (Body Sensor Interface), the combination instrument, the multi-function control unit located below, the radio navigation system, and the autonomous telematics control unit.

All control units, except for the parking assist control unit, have a letter following the numerical designation. For example: BSI 9034B, but the numbers always remain the same.

It is a high-speed CAN (Controller Area Network) device.

I hope you can figure this out.

Have fun and good luck.


Waved.

Sure, you're welcome!
Okay, I'll go ahead and locate the lines and tap into them.
Regards,
Yule.