After installing the KOASON AUDI A4 A5 Q5 android display car stereo, if there is problem of No Signal on the OEM screen side happening,

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

1.Check whether the original car CD host is turned on.
You can press the "FM/AM" button on the original car CD panel to determine whether the original host is working properly. If you can hear the sound of the radio when you press the "FM/AM" button, it proves that the CD host is working properly. If there is no sound, it means that the original car host is not working. Press the power button on the CD panel again to turn it on. If it still doesn't work, further inspection is required.

2.If the LVDS cable is plugged into AUDI A4 A5 Q5 android screen headunit correctly.

3.Enter Android factory mode to check whether the "CAN protocol" is selected correctly. For Low version, select: Q5_3G

Routes: Settings ->Factory (code"2018")->CAN Protocol

4.Select the correct Car Display. For Low version, select 1 or 2.

Routes: Settings ->Factory (code"2018")->Car Display

Note: After selecting the correct CAN protocol and Car Display, wait for 10 seconds and then press the reset button on the side of the panel to restart.