Why can’t my unit play any disc?

Ensure that you have put the disc on the tray. Check whether the disc is put in the reverse side. Check whether the disc is distorted. Check whether the disc is stained or scratched badly. Ensure that the disc format is compatible to the player. Ensure that the temperature inside the car is not too high. If so, cool off till the ambient temperature returns to normal. Replace another disc to insert it into the disc compartment.