As far as I know there is no scheduled maintenance routine, though I think the following is a good idea every 6 months or so.

Remove the kick plate and check under the unit for any leaks.
Many folks find their floor rotted out when they go to replace a dishwasher.
I am a big fan of the trays you can get. They fit under the unit and direct any water out to the front so that you see it on the floor and at least know there is a leak.

My current one is a throw away aluminum drip pan that was big enough to sit under the pump, most of the hoses and the water valve. has about half inch sides on it. This was a cheap alternative to a manufactured tray. I just made sure it could not touch anything electrical. The wife bought it so I am not sure what it was for but I snagged it. Just bend the front edge down so the water will run out the front onto you lino or tile.

Also a good idea to check the holes in the spray arms to make sure they are clear. and check the pump filters.