I have found a problem that will prevent the sliding door on the side of the fuel filler flap to open, as the previous mechanic by passed mine, after reading the manual I saw that the door on the fuel filler flap side shouldn't open if this flap is open, in investigating mine that still open when flap is open I saw that there was a magnetic Reed switch that was by passed/shorted out. The magnet on flap hinge activate the Reed switch to closed and current flows thru switch to door relay that opens the door. If flap is in open position door won't open and gives 3 beeps. If switch or wiring is faulty you will have same problem . Mine was still right but magnet was to far away to activate switch, wedged out magnet and moved it closer solved my problem. I hope this will help any one still batteling with doors.