UART connection to MIB2

Having had to do this recently to try to recover a bricked MHI2, I found the info to be a bit all over the place so thought I would gather it into one guide.

You may well need the guidance of an expert such as @pab567 once connected to the MIB for the next steps in recovery/programming, but this set up will allow them to remote access to you to do so. I take no responsibility for any effect connecting in this way has and am in no way an expert on this process!

Parts required:

TTL to USB adaptor. There’s lots about on Ali or Amazon. Look for CH340 chip and you need to make sure it supports 3.3v. This is the one I used https://amzn.eu/d/03Rt3b1k

Quad lock extension cable. Not completely essential but this is an easy way of connecting to the right pins and also allows you to connect cleanly and reversibly to the existing wiring whilst maintaining all the other connections to the car for testing purposes. https://amzn.eu/d/086O3DlR

Connectors, such as crimp terminals or WAGO connectors.

Laptop

First step is to make up the cables following this guide https://www.scribd.com/document/849387823/Connecting-TTL-adapter-to-UART-on-quadlock-VAG-MIB2

find the correct wires in the quad lock extension cable and then cut them and crimp/connect on the UART connection wires so they connect to the lever plug end of the extension. I added some labels so I could ensure I connected them to the USB adaptor correctly. You may need RCC or MMX connection so I added in the wires for both and then just connected the right ones to the USB adaptor as needed.

Next, prepare the laptop.

Download and install PuTTY https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html

Plug in the USB and find the correct com port associated with it in device manager. Then set up the connection as per the scribd article linked above. Save this as a profile for easy connection next time.

Find the correct password required to login to the MIB based on brand and software version as per this article

https://www.scribd.com/document/464567838/Audi-Mib2-solution

And put it into a txt file so it’s ready to copy and paste.

Now connect to the car. It is essential that the car battery is in a good state of charge. Connect a good quality battery charger during this process. I would highly recommend charging the battery for a few hours prior to starting this process to ensure it’s in a good state.

You can take the MiB unit out of the glove box but I chose to drop down the whole glove box and rest it on a bucket as it allowed access to the fuses and keeps all other wires connected to the MiB.

Remove the 20a fuse (position 12) from the fuse box to power down the MIB unit.

Remove the quad lock from the back of the MIB unit and add in the modified extension you have just made by connecting it to the back of the MiB. And the other end to the quad lock of the car that you’ve just removed from the MiB. Ensure the correct wires are connected to the usb adaptor in the right way and that it is set to 3.3v. Plug usb in to laptop.

My wires were quite short so I had to balance the laptop on the passenger seat. You can extend the wires when making the adaptor but they should not be extended more than a metre.

Open putty and load the profile you set up. You should see a blank black screen. Now copy the password from the txt file.

Insert the fuse for the MiB unit. You should see the screen now being populated with text and code as the client logs the activity of the MiB.

Press enter and type root, then enter then right click on the black background. (This will paste the password you copied) and press enter. If the login is successful you should see “Audi MIB” in ascii characters as per the picture above.

You are now logged in to the MiB. If you are being supported remotely ensure you have an appropriate remote access tool installed to allow your support to control your laptop to enter commands.

Using certain command codes it’s possible to backup to an SD card as well as various things such as remove component protection or update fec codes/ program the eeprom etc. I have no information on how to do this! There is a high chance of bricking your unit so do not proceed unless guided by an expert or you are confident in what you are doing!