There are two options, how to downgrade from EURO4/EURO5 to EURO3. (Disable AdBlue system)
 
1: With VEDOC code and XENTRY
- Calculate  DAS password and VEDOC code with VEI device.
- In DAS Xentry choose Downgrade official procedure.
- Video is here: https://www.youtube.com/watch?v=wDuCS3ffj_o
- Note: some trucks DAS Xentry not supports, and flash files are online in XENTRY database.
 
2: Rewrite PLD flash file.
- In our database: http://autovei.com/en/dump
- Choose a PLD type you have (A1, A2..), Engine model, and EURO III
- From https://my.autovei.com download a flash file you need. (Only for VEI users, with limit 5 files per day)
- Make backup of your flash / eeprom before any operations.
- Write new flash file, and after original EEPROM.
- To disable Adblue light on dashboard, go to XENTRY and turn ADBLUE light OFF (INS, FR module).
- Do not forget to check IMMO and keys status, if truck not start.