Remove the bottom panel and check if the pump is working.
If the motor is not moving but makes a humming noise then replace the pump and motor assembly.
If there is nothing wrong with the motor, check the drain line.
I would start to check the drain line from the air gap on top of the sink (if there is one). Remove the cover and the top piece and check for clog.
Disconnect the drain hose from the air gap, put the end of the hose in a bucket and start the drain. Look for any foreign objects coming out.
Remove the lower dish rack, then remove the filter frame on the back (#543 on the
body break down diagram) and unscrew the piston & nut (#564 on the
same break down diagram). Replace if it's worn out.
If it did not help, remove all water from the dishwasher. Remove the dishwasher from the cabinet. Disconnect the drain hose from the check valve (#560 on the
body break down diagram).
Check the drain hose for any clog.
Replace the check valve assembly.
- The part number for the pump & motor assembly
AP2616850 - The part number for the piston & nut assembly
AP2617344 - The part number for the check valve assembly
AP2039866 - Here are the break down diagrams for the GE dishwasher
Model GSD3400G00CCGene.