After installing the KOASON AUDI A6 2005-2009/Q7 2006-2009 android screen CarPlay , if there is problem of No Signal on the OEM screen side happening,

It is wiring or setting issues, Please check the followings guidance to solve it:

1.Check whether the original OEM car CD host is turned on.

You can judge whether the original car CD host is working properly by pressing the "RADIO" button next to the original car knob. If you can hear the sound of the radio by pressing the "RADIO" button, it proves that the CD host is working properly. If there is no sound, it means that the original car CD host is not working. Press the power button on the CD panel again to turn it on. If it still does not work, there may be a problem with the line or settings, which needs further inspection.

2. Is the LVDS cable wiring correct?
The "MMI" cable on the power cord should be plugged into the MMI cable on the AUDI Android screen.

3. Enter Android factory mode and check whether the "CAN protocol" is selected correctly. Audi A6 05-09/Q7 06-09 models should select: Q7_2G_3G
Routes：Settings ->Factory (code"2018")->CAN Protocol

4.Select the correct Car Display. KOASON Audi A6 2005-2009/Q7 2006-2009 Car stereo models should select: 16 or 17
Routes：Settings ->Factory (code"2018")->Car Display

CAN protocol and Car Display selection，Click for details