Q:
       Hello, we have a problem after installing the Koason monitor. The menu cannot be selected and jumps back immediately as soon as you try to open an app or something else.
 
A:
      For Koason Mercedes-Benz Display with NTG5 models, if the CAN protocol is incorrectly selected, the system will automatically return to the main menu. To solve this problem, please turn on the Bluetooth of your phone and connect to the Android screen. After the connection is successful, you will enter the Carplay or Android Auto interface, then make a phone call at random. At this time, the screen will stabilize, and then enter the Android factory mode to select the correct CAN protocol.
Please check what model your car is, and then follow the instructions below to select the correct CAN protocol.
For Mercedes-Benz C-Class, GLC, V-Class, X-Class, select option 0: 5.0
For Mercedes-Benz A-Class, CLA, GLA, G-Class, E-Class, CLS, B-Class, SLK, GLE, GLS, select option 1: 5.1

Routes：Settings-Factory（Key：2018）-CAN Protocol