Warning. Altering the EEPROM incorrectly has the potential to render your cluster and/or car inoperative. Proceed at your own risk.
A Hex Editing program will also be required to alter the EEPROM coding. I use this excellent XVI32 Hex Editor. There are many others freely available.
The procedure described here is that used with the VagTacho USB program, however the general procedure is similar when using VAGdashCOM
Firstly, ensure your car battery is fully charged. If the car voltage is low then there may be issues with EEPROM flash (incomplete transfer of data etc)
Secondly, ensure the laptop is sufficiently charged to complete the procedure - it may take up to half an hour to complete.
Plug cable into OBD port in car.
Switch ignition to ON position only. Do NOT start car. Ignition must remain ON during entire coding procedure.
Launch program on your laptop/computer.
If VagTacho searches and it is a "VDO New" tacho, then you are set to go.
In VagTacho - select Read the EEPROM.
The program reads the EEPROM and stores it in the memory buffer.
Go to the top of the screen and select "File" then "Save File".
Save the file to your desktop or somewhere as an ".eep" file.
Do NOT exit the VagTacho program.
Just open XVI32 (or other Hex Editor) program separately.
Set the XVI32 program to have 16 columns when you view it for ease.
Go to: "Tools" - "Options" - "Appearance" - "Number of Columns" and make the value 16 to do this.
Now open up the .eep file you just saved.
Magically the full EEPROM dump will appear. :-)
It should begin at 000000 and end at 0007FF
If the EEPROM dump does not end at 0007FF, then it is incomplete. Do NOT proceed any further until you have a proper EEPROM read.
In XVI32 click on "Address" tab, then "Go To"
Type in the search parameter the byte address you are looking for.
Type search enquiry as a hexidecimal address, for example "000416" or "$416"
It will locate the specific byte and highlight it. It will say, for example "C1"
Amend byte to the new value you require, for example "E1", by simply typing in the highlighted field. It will overwrite the existing data.
Save this amended file as a new ".eep" file. Give it a different name to your original file.
Always keep your unaltered original file as a backup copy!!!
Now go back into Vagtacho program.
Select "File" then "Read File".
Select the NEW altered EEPROM dump you just saved and it will load that file into the memory buffer.
You can have a look at the memory buffer if you wish, to make sure the altered figure is recorded properly and the entire dump is ready to load.
Now select "Write EEPROM"
New dump writes into cluster EEPROM. Do not interrupt this process until it completes the task.
When finished press "Disconnect"
Switch off ignition and unplug cable etc.
Please note, it has been observed on some occasions that the alterations may not be immediately visible. The cluster will be operating normally at this point in any case, however, it may take a few minutes, or a couple of start cycles for your alterations to appear. Some people have had to remove the cluster fuse or disconnect the car battery before the alterations take effect.