A01 - Float switch operated*
A02 - Open/Short circuit heater relay*
A03 - Short circuit on thermistor or Time-out drain- Check filter for blockages then book a dishwasher repair if the problem persists.
A04 - Unable to reach or sense temperature within 70 minutes*
A05 - Pressure switch has not been reset*
A07 - Open/Short circuit wash motor triac*
A08 - Open/Short circuit auxiliary wash motor triac*
A09 - Open/Short circuit with main wash triac*
A10 - Open/Short circuit fill valve triac*
A11 - Half load valve triac or alternating motor action*
A12 - Open circuit heater relay*
A13 - Open/Short circuit dispenser triac*
A14 - Drain hose too low causing syphoning. Check drain hose and re-adjust.
H20 - Check tap and pressure of incoming water.

http://www.indesitservice.co.uk/help-and-advice/er ror-codes/