About C4 Screen Display:
Q：I have two MB STAR C4 and everything was fine when I started using them. But after a period of time, its screen shows such problems as the following figure. It can no longer work normally.
A：This may be the cause of the burn-out of the screen. You should connect the computer with a network cable and observe its status. If the main program is lost, it is likely that the main board is broken. You need to return to the factory for repair or click the link below to purchase a new PCB board.
About C4 Self-diagnosis:
Q：I just received c4 from China. I immediately carried out self-diagnosis on it, but it has such problems. What should I do?
A：Are you sure you bought it from us? If you are sure, please reconnect the test. Before we deliver the goods, they have been strictly tested and there will be no such problem.
A Fault on C4:
Q: My C4 Prompt appears “Switch on ignition” when diagnosing my car. What is the problem ?
A:This is probably due to a program error, which requires upgrading C4 and refreshing the program again. If you don’t know how to upgrade the program, you can contact us and our technicians can provide you with free teaching.
C4 motherboard problem:
Q：I have a SD Connect C4，but it suddenly stop working. It can’t read any information out of the car except voltage. Here is the picture of the self test . What’s wrong with it?
A： Powersupply：8 error，you have hardware error, hence no connection to vehicle. You must replace its relay board, please click the link below to buy a new one.
Diagnosing Vehicles with C4:
Q：When Mercedes Diagnostic Tool C4 connect vehivle. Shows errors like the following.It can’t go on .
A：If you connect C4 by network cable. Please check whether computer wires IP is correct.The correct IP address is 172.29.127.101 / 255.255.255.0 ; If IP address is correct. I think C4 have a problem.You need to return to factory for repair .And enter link to buy a new one .