Hotpoint Aquarius Dishwasher not working?

Hi, I bought a Hotpoint Aquarius Dishwasher from eBay a few months ago, sorry don't know the model number. It's probably about 4 years old.

First it was working great, but now if you want to wash on an intensive cycle it stops after about 5 minutes and the wash and dry lights come on and flash constantly.

I have cleaned the filter out and checked for any blockage but found nothing.

All other cycles run their full time, but it's the intensive wash that I need and the only one with the problem.

Please can anyone help.

Thanks

Lisa