I had to replace the drain pump on mine a little while back for the same reason. I realized after the fact that I needed to be more consistent about cleaning the filter.

I have a similar model. there is a filter in the bottom of the inside. it should be a round grey drain. it twists easily in one direction to unlock and then the whole thing lifts up (screen and all).

on the underside is a pre filter, check it to make sure it's clean. if not, clean it in the sink with some hot soapy water.

if that doesn't solve your problem it might be the pump like others have said.

if it does solve your problem regular maintenance cleaning goes a long way. every 3-6 months I run mine through an empty cycle on pots & pans with two tablespoons of powered vinegar and one tablespoon of powdered citric acid.

if you’ve checked all the basics. the issue is most likely the pump.

I changed mine. it is not particularly hard. took me 40m with a youtube video

Failed drain pump seems the most likely scenario, if you’re absolutely proven the pipes are clear - the drain pipe runs through the dishwasher and then cabinetry to the sink drain, and it can be a circuitous path that traps grease.

The thing I learned when I had dishwasher issues was to always start with the manual. You'll probably be surprised with how much info is in the manual.

The Samsung dishwasher I had issues with had 50+ pages worth of diagnostics and repair instructions, including detailed meanings for every unique error code that can occur, and instructions for putting the whole unit into a test mode, where you can force each motor to run independently, run test routines for sensors, etc. Gave me everything I could want for DIY repairs.

Can't say it's always this nice, of course, but this adivce has served me well for other appliances since.

Have you removed the drain pump yet? Chances are there is a piece of bone, glass, cherry pit, crayon, zip tie, bread tag logged in there.

Certain styles use a replaceable magnetic impeller that gradually loses its fins. Ours became noticeable at 4/6 fins and wouldn’t drain at all by 2/6 fins.

Might be fat clogging the pump. I had this one time, called the repair company and the guy pullednojt a syringe and pushed water into a hole and a big block of fat popped out - 5 minutes work. Machine drained afterwards without an issue.

He told me that this frequently happens when people only use the low temperature program and that you should run the high temp program (70c) at least twice a month.

Mine has a sensor in the drain much further down than the filter. If someone spilled detergent inside the machine, it will make a lot of bubbles, and this is enough to trigger the sensor, so it refuses to run the pump.

In order to flush it, I need to move it out, so I can open the safety drain on the back and throw in a bucket of water, collecting the water from the safety drain on a towel.

Drain it and disassemble in the bottom until you find a metal ball in front of a whole. Both maybe the size of a marble. You won't probably be able to remove the ball, but clean around it and make sure its not stuck. I found all kinds of stuff there. Alcohol or dish washing soap help with the fat and stuff.

There are two pumps in a dishwasher: drain and circulation. Each has a capacitor which can be replaced if it blows. In my 25+ year old dishwasher, this is the only thing that breaks from time to time.

Should be less than 10 bucks including shipping.

Edit: sounds like some models use a solenoid with one pump instead. Open the machine and investigate.

Have the exact same dishwasher and had a similar problem at the beginning of the year. After days of troubleshooting, ended up having to call for a repair unfortunately. I believe in our case it was both the pump and impeller (the parts that take the water/sludge and get them out of the dishwasher, not the water filling it)

You can buy a special dishwasher cleaning powder that can better deal with fat build up in the internal drain. Sometimes that helps and it is the least messy option.

Does the motor/pump work at all, spraying water around inside? If yes, and there are no clogs, check the drain solenoid - it should actuate a valve that directs the pumped flow of water through the drain pipe instead of the sprayers.

Prepare for mess, you can try and go in the back but it's likely clogged with shite beyond what sanitize mode can deal with.