The short answer
A dishwasher that has stopped cleaning properly usually comes down to one thing: the filter stack is fouled. Next on the list: the spray arm jets are blocked. Note the pattern first — whether it is the whole load, one rack, or one kind of item — because that decides which of these it is.
What you observe
- Dishes come out needing to be washed again — Note whether it is the whole load or only part of it.
- A gritty film on glasses and the insides of cups — Debris is being carried back rather than carried away.
- The same part of the rack is dirty every time — A repeatable pattern points at a fixed obstruction.
- One whole half of the load comes out dirty — A stalled arm washes one sector and abandons the rest.
- NEAR MISS — dishes are clean but come out wet — That is a drying and rinse-aid question, not a cleaning one, and it belongs on a different page.
Causes, most likely first on this machine
- The filter stack is fouled — First on this machine and it is not close. A modern dishwasher recirculates its wash water continuously, so anything the filter does not hold goes straight back onto the dishes.
- The spray arm jets are blocked — Ranked here because a blocked jet leaves a repeatable pattern, which is the most useful clue on the whole page.
- The spray arms cannot turn freely — Ranked here because it is free to check and because on a tightly-packed machine it happens constantly.
- The water is not arriving hot enough — Last, and tested for free by running the hot tap at the sink before starting.
Check in this order, and why
- Lift the filter stack out and look at what is in it — A dishwasher recirculates its water, so the filter decides what ends up back on the dishes.
- Take each spray arm off and hold it up to the light — A blocked jet always dirties the same part of the load.
- Spin each arm by hand with the racks loaded — An arm that catches is an arm that stops in service.
- Run the hot tap at the sink before starting a cycle — A machine fed from a cold pipe never catches up on a short programme.
What an owner can safely check
- Note exactly what comes out dirty and where it sat — Whole load, one rack, or one kind of item — each points somewhere different.
About 10 min
- Remove the filter stack, rinse it under a hot tap and refit it — Twist it fully home; a filter left loose lets debris past.
Tools: warm water, brushAbout 15 min
- Remove each spray arm and clear the jets with a cocktail stick — Rinse them through before refitting.
Tools: cocktail stickAbout 20 min
- Load the machine as usual, then spin each arm by hand — If it catches anywhere, move the item that caught it.
About 10 min
- STOP HERE before removing the heater or the wash pump — Those are behind the tub with live terminals nearby. Service call.
Before you open anything
Safety
Switch the machine off at its spur or breaker before removing any panel, and close the isolating valve before touching a hose. A capacitor can hold a charge after the power is off. Broken glass finds its way into the sump and the filter on any machine. Use gloves when clearing a filter, and never feel blind into a sump you cannot see the bottom of.
When to call a technician
Call once the filter is clean, the arms turn freely with the racks loaded, the jets are clear and the dose is right, and dishes still come out dirty. At that point it is the wash pump, the heater or the diverter, and all three are behind the tub. Call immediately if the machine trips the breaker, or if there is a burning smell during the wash.
Nearest pages of this class
What this page does not cover
This page is written for the brand and the machine class, not for one family or model line. Where a family- or model-specific page exists for your machine, it is the more specific answer and it is where to start. Deliberately absent: programme charts, place settings, pump and board part identifiers and wiring colours, which differ between the freestanding, integrated and panel-ready families.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
