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Parts for Frigidaire PLD4555RFC0 Dishwasher - AppliancePartsPros.com
The fill valve is item 3 in the Frame Parts section.
You should be able ti fix this without pulling the dishwasher.
I am assuming that the fill velve is the problem and the unit does not fill to the correct level but does let some water in.
The most common cause is a dirty screen filter on the input side of the fill valve. Remove the valve from the unit and clean/check the filter.
Do not permanently remove it from the valve as it is there to keep crud out of the valve which could hold it open and cause a flood.
If it still does not fill correctly I would replace the fill valve.
PS: Be sure to shut off the power and the water supply to the unit. Have paper towels etc. handy to wipe up any spilled water. Get a small pan/bowl etc. that will fit under the valve then loosen the input water line let it drip into the container emptying it as necessary. This will minimize the amount of water spilled.