Samsung’s dishwasher article lists 5C, SC, 5E and SE as a single drain error: the dishwasher cannot drain. On the seven-segment display the 5 and the S are the same character, so the four spellings are one code. Water still sitting in the tub when a cycle ends, with no code, is the same problem caught later. The drain path is filter, sump, pump, hose and the connection under the sink, and the first two and the last two are owner territory.
The Filter Assembly
With the dishwasher switched off at the breaker and the water inside cooled, remove the lower rack and inspect the tub floor. Samsung dishwashers use a cylindrical fine filter that twists out of the sump, with a flat mesh filter around it and, on many models, a coarse filter cup inside. Twist and lift the assembly out the way the manual for your model shows, rinse each part under the tap with a soft brush, and look for the things that stop drains: a broken shard of glass, a label from a jar, a toothpick, a build-up of grease that has set into a wax. Shine a torch into the sump opening and lift out anything you can see. Refit the parts in order and twist the fine filter until it locks; a filter left unlocked lets debris into the pump.
The Drain Hose and the High Loop
Under the sink, the dishwasher drain hose should rise to the underside of the counter before it drops to the sink drain or the disposer. That high loop is what stops sink water flowing back into the dishwasher and what lets the pump push against a clean head of water. A hose that sags in a low loop holds a slug of water the pump has to move every cycle, and a hose that is kinked behind the cabinet stops it completely. Check the hose for a crushed section where the dishwasher was pushed in, and for a clamp that has slipped.
The Disposer Knockout
Where the drain hose goes to a garbage disposer and the dishwasher is new, or the disposer is, check that the knockout plug inside the disposer’s dishwasher inlet was removed at installation. A disposer ships with that inlet sealed, and if it is still sealed the dishwasher cannot drain at all, on every cycle, from day one. With the disposer switched off at its switch and its breaker, disconnect the dishwasher hose at the disposer and probe the inlet with a screwdriver; a solid wall is the knockout, and it is punched through into the disposer chamber and fished out.
Air Gap and Sink Drain
Kitchens with an air gap fitting on the sink deck route the dishwasher hose through it, and the air gap itself blocks with food. With the dishwasher off, lift the air gap cap and clear it. A sink drain that is slow on its own account will back up into the dishwasher hose too; run the sink and watch it drain before blaming the dishwasher.
The Pump and the Check Valve
A clean filter, a clear hose and a drain code that returns leave the drain pump and the check valve at the sump outlet. A humming pump that shifts no water has a jammed impeller, often from a piece of glass that got past the filter; a pump that is silent has a motor or wiring problem; a check valve stuck open lets the water the pump just removed run back into the tub. Those are reached with the dishwasher pulled out and the power off, and they are a visit. Book a Samsung dishwasher repair and say whether the pump can be heard running as the cycle ends and whether the filter has been cleaned.