You have entered the code wrong, you need to leave the unit powered up until it will take the code again. If you got the code wrong once, you wait 1min, wrong twice is 2mins, three times is 4mins, four is 16mins and five is 4.26hours etc etc(its an anti theft idea) you must leave power applied to the unit, so if your ignition shuts off after a while, remove the unit and leave it connected overnight to a suitable power supply, then try again. Hope this helps.
Paul Bell, April 2008