How can I fix mt Bosch Exxcel ?

Hi there - sod's law the guarantee has just run out. The machine is 3 years old. Instead of the usual 35 minute quick wash I set it on a long wash, but after 20 minutes, realised how much lecky it was using, so I switched it to the quick wash. It doesn't appear that water had gone into the machine as the dishes were still dirty. We have checked the hoses, cleaned the filters etc. Could this be the pump? The check water light was on, but we then reset and it goes out, but as soon as we press start, it comes on again. Your help would be invaluable.

Thanks