AEG Single Oven Fault Code F102

Hi, I have a AEG Oven, model BPK842720M with a fault code F102. Its a single oven and grill combined. The grill works fine with the door open but none of the oven settings work for more than 10 seconds with the door closed. The oven does heat up if you keep resetting it but switches off after ten seconds with the fault code F102. The micro switch on the door is working as the oven light turns on and off. Any ideas?