malfunction lamp lit

I disassembled to clean the air filter. I wonder if the malfunction lamp did not light up for 2 years.

automatic gearbox car?

The lamp itself does not go out, I guess, because it found an error and recorded it in memory. Learn the error code of connect to the device in places such as service.

Manual gear lpg. I added gasoline to the tank a week ago.

drive for about 50 km on gasoline, possibly self-extinguishing fault light