Can you advise whats shown on the display after the dishwasher fails to empty?
The fact your not hearing any noise from the pump would suggest the pump has failed, with a block pipe or filter you would hear the filter running and struggling to pump.
Most pumps cost around £30 to replace, I am struggling to locate your model number can you confirm its not DL1243AP
Pumps are generally common faults on dishwashers across all brands to be fair.
There should be a overflow sensor in the dishwasher, normally looks like a mushroom float which sits near the salt cap and filter. If you pull this up this up with the dishwasher on, even if not set on a program the pump should start, as the flood safety feature overrides everything.
If you cant find the float another way is to tip two buckets of water in the dishwasher to the point where water is about to come out when the door is opened, if the pump doesnt start then either its highly likely to be the pump.
Another fault finding step involved stripping the unit down and checking the voltage going to the pump, and also doing a continuity check on the pump (it shouldnt be open circuit).
Capacitors are not needed for small pumps, as there isnt a great deal of back EMF generated.
Ok so we know the pump is working as you can make it spin, so the fault has to be with the dishwasher not calling the pump.
There should be a float in the sump detecting level of water, I would find that and see if you can manually actuate that, if you can you then want to check your getting a voltage across the pump terminals.
This sounds like it may well be the control board, if your not getting a voltage out to the pump though.
If your going to do that check the connections going to the PCB and do a continuity test to prove the sensors are working and there are no broken wires on the harness.
I cant really think what else would give a fault, or why your not seeing a valid error code shown on the display panel, so a replacement PCB would probably be the next step (and a good price at £40).
I havent heard back from you in the last day or so, and just wanted to check if you still require assistance, I would appreciate it if you could rate the service received.