AEG 40850 favorit?

My AEG Favorit 40850 works for a few minutes then displays 20 code. In the manual this means a drainage problem. We have put water in the bottom of dishwasher and also cleaned through with a hose pipe. The water was pumped out ok. After that it worked on 30 minute programme tried automatic programme same error code appeared halfway through the programme. Then tried 30 minute programme did not work after 5 minutes. This dishwasher has been nothing but trouble since I bought it. Had 3 new control panels and numerous other problems extended warranty now expired. After reading peoples dishwasher problems would not know which one to buy. Previously had a bosch and also a philips both were fine.