The short answer
Standing water in a SMU tub is a blocked path far more often than a dead pump. The seven codes in the table share the family stem and sit close together in build, so the layout described here holds across them.
What you observe on these models
- Clean water standing in the sump after every cycle — Clean water means the wash finished and the drain failed at the end.
- The machine hums at the end of the cycle but the water level does not move — The pump is being asked to run and cannot turn, or it turns against a blocked outlet.
- The cycle stops part way and the panel shows a fault — Most controls abort the cycle once the water is still there after a drain attempt.
- NEAR MISS — water under the machine rather than inside it — That is a leak, not a drain fault, and it has its own page for this family.
Causes, most likely first on the SMU family
- The filter and sump are packed with soil — First, and it is free to check. The filter twists out by hand; if the sump under it is holding soil, the pump has been trying to push it through and failing.
- The disposal knockout plug was never removed, or the disposal is full — Ranked second on a family this young, because it is the classic new-installation fault: the dishwasher hose was connected to a disposal whose knockout plug is still in place, and the machine has never drained properly.
- The drain hose is kinked, trapped or has lost its high loop — Third. Check it before anything electrical: a hose with no high loop siphons the sink back into the tub, and a kink behind the cabinet stops the drain dead.
- The air gap on the counter is blocked — Only some installations have one; where it exists, it is the cheapest thing on this list to clear and the easiest to forget.
- The drain pump has failed electrically, or the control is not calling it — Last. A pump that makes no sound at all when the drain step should run points at the pump winding or at the control that drives it, and either one is a service call.
Check in this order, and why
- Run the drain or cancel function first — It forces one clean drain attempt with nothing else happening, so you can hear whether the pump runs, hums or stays silent.
- Bail the tub out and pull the filter — Scoop the standing water with a cup and a towel, then twist the filter out and look in the sump with a light.
- Check the sink side before the machine side — Run the disposal, check the hose behind the cabinet for a kink, confirm the hose rises into a high loop or air gap, and clear the air gap cap if one is fitted.
- Look at the pump inlet with the power off — With the breaker off and the sump dry, the pump inlet under the sump screen is where a bone chip or a piece of glass lodges.
- Stop here if the pump is silent — A drain step that produces no sound at all, with a clear filter and a clear hose, is an electrical fault at the pump or the control — and that is where the owner-side list ends.
Models in the SMU family — Each code here is pinned to a single build, so match the tag inside your door frame character for character. The seven codes fall into four leading groups, and that spread is the reason this page is written for the family rather than for one machine.
Reference| Model number | Family key |
|---|---|
| SMU2ITS01A | bosch:dishwasher:smu |
| SMU4HTS01A | bosch:dishwasher:smu |
| SMU4HVS01A | bosch:dishwasher:smu |
| SMU6HAS01A | bosch:dishwasher:smu |
| SMU6HCS01A | bosch:dishwasher:smu |
| SMU6HCS02A | bosch:dishwasher:smu |
| SMU8ECS01A | bosch:dishwasher:smu |
Before you open anything
Safety
Switch the breaker off before you reach into the sump or take the toe-kick off — a capacitor can hold a charge after the power is off, and you will be working with your hands in water. Assume there is broken glass in the sump, because there usually is: use a glove and a light, not bare fingers.
When to call a technician
The owner side of this fault ends at the pump inlet. Filter, sump, drain hose, air gap and disposal are all reachable with a towel and a torch, and they account for most of these calls.
Other symptoms covered for this family
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
