kitchenAid dishwaher loss of water pressure

My dishwaher will fill with water but when the cycle starts thers not enough water pressure to turn sprayer arms. motor seems to run but only to shoot small amount of water from lower arms not upper at all. do i need a new motor or something else?

Here are your parts
Replacement parts for WHIRLPOOL KUDS01FLSS0 DISHWASHER | AppliancePartsPros.com

Here isn a manual which should help.
https://secured.whirlpool.com/Service/SrvTechAdm.nsf/2cd44500d572193285256a45004fd9d6/4e8b0d2df77cd7e585256cd800643b6d/$FILE/KD01.pdf

Often poor wash results are due to a low fill level or dirty pump filters/chopper/impeller.

The easiest to check is low fill.
Most units fill to just under the heating element.
After a fill add a couple quarts of hot water. Be careful to not overfill the unit. Now if it washes OK I would say you have a low fill problem.
The most likely cause is a partially plugged screen filter which is built into the input side of the fill valve.
Remove the valve from the unit and check/clean the screen 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 low fill is not the problem, dismantle the pump and check/clean the filters, the chopper and the impeller.