There are 17 KOASON Audi screen models. Each AUDI model has different CAN protocol options and Car Display parameters according to the year. If the wrong selection is made, the original car CD host cannot be started and the original car has no signal.
You need to enter the Android factory mode to select the CAN protocol and Car Display.
Routes：Settings ->Factory (code"2018")->CAN Protocol

Car Display：

Year, CAN protocol and Car Display comparison table:

Note: After selecting the correct option, wait 10 seconds and then press the reset button on the side of the screen to restart for it to take effect.

Reset button location for each model:

2009-2016 A4/A5，2010-2017 Q5：

New Audi A1 A3 A4 A5 A6 A7 Q3：

2005-2011 A6 LHD（OEM Style）：

2005-2011 A6 RHD（OEM Style）：

2006-2015 Q7 LHD（OEM Style）：

2006-2015 Q7 RHD（OEM Style）：