Byte 18 set to 04. Mine fitted as standard rear leds and retrofitted led bi xenons. Did change byte 19 tho as that regulates the voltage to front and rear lights. Byte 19 is currently set at 86 from 00. Did do a spreadsheet with varying codes on many cars to see what the problem was with my bulb error and most cars are set to either 04 or 00. I did have VCDS and still can get access. It was the latest release and did have many options on a drop down menu.