(like "EC 80") on the screen, or is it just the general "Insert Map Disc" message?
In some cases, the internal firmware (the software running the stereo) may be outdated or corrupted. If you can find a compatible firmware update for the NDDNW56 model on the manufacturer's website or through a dealer, burning this to a disc and inserting it can sometimes clear the "Insert Correct Map Disc" error. please insert correct map disc nddnw56 work
