The short answer first
Short answer: a blockage, not a breakdown. Start with the drain hose crushed behind the machine on this machine. A pump that has actually failed is the least common cause here and the only one that needs a technician.
What this looks like
- Dirty water with food debris sitting in the tub — Debris in the water points at the filter and the sump rather than at the pump or the hose.
- Nothing at all happens during the drain phase — complete silence — Silence where there should be a pump points at the electrical side rather than a blockage.
- A smell from the tub between cycles — Standing water and trapped food do this within a day or two, and it clears as soon as the blockage does.
- NEAR MISS — the machine will not start at all — No cycle and no lights is a power, door-latch or control fault, and a different page covers it. Drainage faults happen at the end of a cycle, not before it.
What goes wrong here, in order
- The drain hose crushed behind the machine — The drain hose is the longest part of the path and the only part that can be physically damaged by moving the machine, which is why so many of these faults date from the last time the kitchen was cleaned. It comes first for a practical reason: the check takes minutes and it decides which half of this list you need. With a badge of this size the sensible order is the one that gets you to an answer without waiting on a part that may take weeks to arrive.
- The filter stack packed with food debris — A dishwasher recirculates its water many times during a cycle, so the filter is doing its job constantly rather than once. It loads faster than owners expect and it is the first restriction water meets on the way out. Next in order: it explains a smaller share of these faults but is quick to confirm once the first is clean.
- Blocked sink trap or shared waste line — A dishwasher discharges into the same waste as the sink beside it. If that trap or branch is partly blocked, the machine cannot push water into it, and water may even return the other way when the sink is used. Third in the order: less common than what precedes it, and more work to confirm.
- The drain pump itself, electrically failed — The distinction that matters here is between a jam and a failure. A pump that hums is powered and obstructed; a pump that is silent when it should run is an electrical fault, and that is a technician's diagnosis. It ranks last on the evidence rather than on its importance: when it is the answer, it is unmistakable.
The order to check in
- Feel along the hose where it passes behind the machine — A hose flattened between the cabinet and the back of the machine is hard to see and easy to feel. Do this first: it settles the likeliest cause before any tool comes out.
- Twist out the filter in the base of the tub and look at the mesh — A film you can see through is fine; a mat of debris is the fault, and it is visible the moment the filter is out. Follow with this: it either confirms the second cause or clears it for good.
- Watch the sink while the machine drains — Water rising in the sink as the machine pushes is a shared-blockage signature. Third, and only if the two above found nothing.
What an owner can safely check
- Straighten the hose and secure the high loop up under the worktop — Use the clip the machine came with, or a cable tie to the cabinet wall.
Tools: cable tieAbout 20 min
- Bail the standing water out, then clear the sump by hand — Use a jug and a cloth; wear a glove, because broken glass is common in a sump.
Tools: jug, cloth, gloveAbout 25 min
- Clear the sink trap over a bucket and re-test both the sink and the machine — Have the trap seals to hand; they are the usual casualty of opening one.
Tools: bucket, glovesAbout 35 min
- STOP before testing anything electrical with the power on — The checks above are all done cold. A test that needs power applied is a technician test, whatever a video shows.
Safety first, and it is not boilerplate
Safety
Switch off at the socket or isolator first; a capacitor and mains terminals sit behind the door panel. Use a glove and a torch rather than bare fingers when clearing a sump, and never mix cleaning chemicals in the tub while looking for a smell.
The line between a fix and a call
The owner-side work ends at the sump opening. Anything that needs the machine pulled out, the pump housing opened or a circuit tested is a service call — and it is worth booking with the checks above already done, because that is what makes the visit short.
Nearby pages
What this page leaves out
This is the generalized page for l2 dishwashers. If a page exists for your particular family or model line, it is linked from this section and it outranks this one for your unit. What is deliberately absent: part numbers, connector pinouts and the service-manual sequences, which are family-specific and wrong the moment they are generalized.
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
