When removed,the Nav unit will have a serial number stamped into the casing on one side, take this code to VW (with some ID, V5 just in case!!) & they'll get the correct code... doesn't take long. Then (here's the important bit!) you need to leave the ignition on to 2nd position, then turn the Nav on for about an hour... after this the unit will stop reading 'safe' on the screen, you'll be able to select the numbers to add the code again & all will be fixed! Driving the car with the Nav for an hour doesn't work... I tried! It has to be ignition on, & NAV on, also it can't be re