Bosch Exxcel starts, then 30 secs later flashes E15 then 0:00 & stops ?

I have a Bosch Exxcel dishwasher that is just over 2 years old ... ie just out of warranty.

It has worked fine right up until about 1 week ago when it stopped working properly. It would start * make a noise that sounded like the pump working then after about 30-60 seconds it would make a noise like it was draining then flash the code E:13 briefly then go to 0:00 & stop.

I checked the water supply and adjusted the tap so that it had a greater flow of water coming through. After that it worked fine, other than the fact that it would switch off when you pushed the on/off button.

Now it has developed this fault again, only this time I can't find an obvious fix. I have checked the water supply which is fine. I have tried tipping it to drain any water out - there was a little but not much. I have been though just about every related post on this forum but haven't quite found the same issue reported elsewhere.

Any suggestions anyone?