Samsung’s washer article groups nd, 5E, SE, 5C, SC and the combo spelling 1 5C as one problem: water is not draining from the washer at the correct speed, or at all. The washer keeps the door locked as long as water remains in the drum, which is the right behavior and the reason the code feels like an emergency. It is not one. The drain path on a Samsung front-loader runs from the tub through a pump filter to the pump and out through the hose, and the first two of those are yours to check. The sequence matters because the alternative is several gallons of water on the floor and a wet hand in a machine that is still connected to the mains.
First, the Hose and the Standpipe
Before opening anything, look at the gray drain hose at both ends: behind the cabinet where it exits, and at the standpipe or sink connection. A hose crushed behind the cabinet, a hose pushed so far into the standpipe that it seals and siphons, or a standpipe that is itself blocked all produce a 5C. If the hose is clear and the standpipe drains a jug of water freely, move on.
Getting the Water Out Safely
With the washer switched off and unplugged, or its breaker off if the plug is out of reach, and with both supply taps closed, open the small service flap at the bottom of the front panel. It hides the round pump filter cap and, on most Samsung front-loaders, a short emergency drain hose with a stopper. Put a shallow pan and a towel on the floor below. Pull the small hose out, hold its end over the pan and remove the stopper; let the water run until the flow stops, refit the stopper and tuck the hose back. Do not unscrew the filter cap while the drum is full: the water behind it comes out faster than a pan can take. On some models there is no small hose and the filter cap itself is the drain, in which case turn it only a quarter turn at a time with the pan pushed hard against the cabinet, and pause while the pan fills.
The Pump Filter
With the drum empty, unscrew the filter cap fully and draw the filter out. You will usually find what caused the code: coins, a hair grip, a sock, a build-up of lint and hair, or a plastic bra wire wound around the pump impeller behind the filter. Clear it, rinse the filter under a tap and look into the housing with a torch. If you can see the impeller, turn it with a finger; it should move freely with light resistance. Refit the filter and screw the cap firmly, since a loose cap is the commonest cause of a leak after this job. Close the access panel, open the taps, plug the washer in and run a short rinse and spin with the drum empty. Watch the panel area for drips.
A Clean Filter and a Repeat Code
A clean filter, a clear hose and a repeat 5C leave three suspects that are not owner tasks: a drain pump whose motor runs but does not move water, a pump that does not run at all, and a control or wiring problem between the two. All of them are tested with the cabinet open and are technician work.
A Note on the Suds Pause
If the washer showed SUd before the 5C, too much foam may be the reason the pump could not clear the tub. Samsung treats SUd as a notice rather than a problem, but a SUd that turns into a drain code is telling you the detergent dose and the drain need attention together. Book a Samsung washer repair if the code comes back after the filter is clean, and say whether the pump could be heard running at the end of the cycle.