My car use to blink the D4 light every time i start the engine,i don’t know why?
It is because the transmission senses an error and is telling you it needs to go in for diagnostics and service.
A blinking D4 light is the “check engine light” for the transmission. You can take your car to an auto parts place like AutoZone and they will read the codes for free. Post the code here and we can help. They will also offer suggestions but we really only need the code. It will be a P07xx or P1xxx format.
It’s good you stopped by to ask about this. If you get it diagnosed quickly, it may be possible to fix the transmission. If you wait too long, it may need to be replaced.