Bosch Maxx5 Fault

Hi, please can someone help/offer advice with a problem with my Bosch Maxx5 Washing machine. Up til now I have been getting an intermittent fault where the machine will go through its regular cycle and sometimes stop at "1" minute left on the digital display, which means the door will not open. The problem is now permanent. Any suggestions on what the problem is and also how do I open the door to get my wash out. I have tried all the programmes, but the machine still displays "1" at the end of each one. I thought the problem might be a blocked pump, so took that off and a 10 pence fell out along with a couple of small twigs. I cleaned it up, and I thought great, problem solved. However, on reassembly the same problem is there. Any help would be greatly appreciated. The machine is about 6 years old so I am thinking maybe a component in the circuit board is failing or has failed. I have two options. One try and find/fix the fault myself or buy a new machine. I do not think it would be cost effective to call out a Bosch service engineer who will charge £100 just for a call out.

thanks

Gary