When the w5w bulb in rear plate is replaced with a led bulb (even if it's canbus error free) an error is displayed in the Infotainment. It's possible to use VCDS for using led bulbs:
-> Controller 09 - Central Electronics
-> 16 - Security Access - enter 31347
-> 10 - Adaptations
Change the 2 channels listed below
(1)-Leuchte25KZL HA59-Lasttyp 25 - set to: 43 - allgemeine LED
(6) Leuchte25KZL HA59 - Dimmwert AB 25 - set to 127
Here you can see th