Here is a parts breakdown
Replacement parts for General Electric GSD4200J00BB Dishwasher | AppliancePartsPros.com

I doubt it is a timer problem.

Sounds more like low fill or a pump problem.

Check that the holes in the spray arms are clean.

Remove the sump cover and check for debris in the sump or something wrapped around the chopper. Be careful as there is often broken glass in the sump.

Another common problem is the unit not filling with enough water.
Most units fill to just under the heating element.
This can be checked by adding a couple quarts of water after each fill during a cycle. If it now washes OK then check the fill valve.
Just be careful to not overfill it.
Often if the fill is low you will also hear a growling sound because the pump will cavitate (suck in air).
The most common cause is a dirty screen filter on the input side of the fill calve. 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.