Meiko FV40.2 errors 203 and 304 popping up

When trying to turn the dishwasher on it usually can't get past the err 304. When it has made it past this point it will read err 203. I'm trying to find out the different reasons for these errors and a service manual to help walk me through the repair. I've not done much work on dishwashers before but have repaired many other machines and problems in the past with little difficulty. Is there anyone who can point me in the right direction?