Fault with Integrated Diplomat ADP8342?

Problem started last night. Before finishing a cycle the dishwasher kept beeping - cycle appeared finished. now unable to start a cycle without it beeping - 3 of the program lights flash - this stops for a moment and then starts beeping again until the dishwasher is opened and power turned off. I have checked for obvious blockages but can't see anything? Please help. Don't have manual as this was installed before we moved in.