VW CanBus decoding

Projects General Guidance
1

Hello guys!

I am working on a project for my car, a 2009 Volkswagen.
My goal is to achieve two things:

  1. RGB Ambient lighting
  2. CAN-Bus decoding to achieve functions like automatically folding mirrors.

This thread will focus on the CAN-part of the project.

I have got the UNO, the CAN shield and a set of CAN wires, but I am struggling with initial decoding of my CAN network to find the correct CAN-Bus messages.

First and foremost I want to find:

  • The message ID and bit that activates the folding mirror motor (This is activated by a knob in the door)
  • Something that tells me if the engine is running
  • Something that tells me if the doors are locked or unlocked

Using the arduino to filter out and find these messages is way out of my league, so I was hoping I could use my PC and USB-OBDII adapter to hook up to the OBDII port of my car, and filter out the packages easily from the PC.

Any ideas? I did all the searching I could. Sorry if violating forum rules here!

2

A proper VAGCOM cable and a copy of VCDS from RossTech will be invaluable for custom programming your VW.
I'm cheap, I used an ebay VAGCOM cable and got it working, and using the free version of VCDS does all I need, but the full version is worth it if you need more.

3

I have proper VCDS and cable - But these functions are limited by the comfort module in the car. The mirror folds, but not automatically. No Passat B6 does this :slight_smile:

4

How do your mirrors fold? Rotary knob near A pillar that also controls heated mirrors or some manual input? Just looking for an automated knob replacement tied to ignition then? That's not a canbus issue if it's not already electronically controlled.

5

You are correct. The knob sets a CAN-bus variable. I can also manipulate this from the test/diagnostics of the VCDS.

I can, however, not program the mirrors through the RossTech interface to automatically fold.
This is the function I want to achieve - But I need to find out what bit on which message ID on the CAN-Bus is activated by the knob in the door near the A-pillar :slight_smile:

6

So you're sure the knob is just a signal and not actually routing power to the mirror motors with a separate signal to canbus? Because if the knob is actually physically breaking the power to the mirrors, no amount of programming can overcome that.

7

I'm sure - Because I can enter with the VCDS software, and go to the testing routines of each control module (I'm not sure if you're aware of this - But I think you are given your knowledge on the subject).

From here, I can run windscreen wipers, horn, high beams, dynamic headlamps, hazards etc. Including folding mirrors.

I am absolutely sure, that this is a programmable project. The PC does, after all, do all of this magic over the very same CAN-interface I plan on using :slight_smile:

8

Hello.
I have a Volksgem and am trying to access data from comfort ids, like lights, etc. Have you been able to find and identify these signs in your project?