The short answer
A Cosmo dishwasher that starts and then stops, or that runs forever without finishing, is usually waiting for something it cannot get: hot water, a full fill or a clear drain. The control extends or halts the cycle rather than reporting the underlying supply problem, so the fix is upstream of the machine more often than inside it.
What you are actually seeing
- The cycle stops partway with water still in the tub — Means: on-page
- The cycle runs far longer than its stated time and never ends — Means: on-page
- The machine pauses at the same point every time — Means: on-page
- The cycle restarts itself from the beginning — Means: on-page
- The display shows time remaining that does not count down — Means: on-page
- The machine never begins a cycle at all — Means: different-fault — Go to: cosmo-dishwasher-wont-start
- The cycle completes but the tub still holds water — Means: different-fault — Go to: cosmo-dishwasher-drainage-failure
- Body: Match what you see before you take anything apart. The cycle stops partway with water still in the tub. The cycle runs far longer than its stated time and never ends. The machine pauses at the same point every time. The cycle restarts itself from the beginning. The display shows time remaining that does not count down. Some near-miss symptoms belong on a different page: The machine never begins a cycle at all points at a start or interlock fault, covered on cosmo-dishwasher-wont-start; The cycle completes but the tub still holds water points at a drain fault, covered on cosmo-dishwasher-drainage-failure.
Causes, ranked for this machine
- A restricted or closed water supply, so the machine waits for a fill it never completes — Why this rank: First because a machine waiting for water looks exactly like a machine that has stalled, and the supply valve under the sink is the most disturbed part of the installation
- A cool hot supply, so the control extends the heating step indefinitely — Why this rank: This produces a cycle that runs for hours without any error at all, which is the most confusing version of this fault
- A restricted drain, so the machine cannot complete a drain step and pauses — Why this rank: Directly linked to the filter and the drain path, and it is free to check
- The door being opened mid-cycle and not properly re-latched — Why this rank: The machine holds where it was and can look stalled, which owners rarely connect to the interruption
- A failed sensor, valve or control board — Why this rank: Last because it needs a part and everything above it is free to rule out
- Body: Ranked for a built-in kitchen dishwasher with an electronic control, a manual filter and a drain hose running to a disposer or an air gap. Most likely: A restricted or closed water supply, so the machine waits for a fill it never completes. First because a machine waiting for water looks exactly like a machine that has stalled, and the supply valve under the sink is the most disturbed part of the installation. Next most likely: A cool hot supply, so the control extends the heating step indefinitely. This produces a cycle that runs for hours without any error at all, which is the most confusing version of this fault. Third: A restricted drain, so the machine cannot complete a drain step and pauses. Directly linked to the filter and the drain path, and it is free to check. Fourth: The door being opened mid-cycle and not properly re-latched. The machine holds where it was and can look stalled, which owners rarely connect to the interruption. Fifth: A failed sensor, valve or control board. Last because it needs a part and everything above it is free to rule out.
What to check, in order
- Check the water supply valve under the sink is fully open
- Run the kitchen hot tap until hot, then restart the cycle
- Clean the filter and confirm the machine drains fully
- Note the exact point in the cycle at which it stalls
- Body: Each check rules out the causes above it. First, check the water supply valve under the sink is fully open. Second, run the kitchen hot tap until hot, then restart the cycle. Third, clean the filter and confirm the machine drains fully. Fourth, note the exact point in the cycle at which it stalls.
Checks you can safely make yourself
- Open the cabinet under the sink and confirm the supply valve is fully open, not part turned — Tools: torch — Time estimate: a few minutes
- Run the kitchen hot tap until the water is hot, then start a normal cycle immediately and watch whether it progresses — Tools: none — Time estimate: one cycle
- Switch off at the breaker, remove and clean the filter, then restore power and run a short cycle to confirm it drains — Tools: brush, gloves — Time estimate: half an hour
- Start a cycle and write down the elapsed time and the displayed step when it stalls, because that is what a technician needs — Tools: notepad — Time estimate: one cycle
- Power the machine down at the breaker, restore power, close the door firmly and run a short cycle without opening it — Tools: none — Time estimate: one short cycle
- Body: Checks an owner can make with the machine switched off at the breaker, or by watching a cycle. Step one: Open the cabinet under the sink and confirm the supply valve is fully open, not part turned. Tools: torch. Time: a few minutes. Step two: Run the kitchen hot tap until the water is hot, then start a normal cycle immediately and watch whether it progresses. Tools: none. Time: one cycle. Step three: Switch off at the breaker, remove and clean the filter, then restore power and run a short cycle to confirm it drains. Tools: brush, gloves. Time: half an hour. Step four: Start a cycle and write down the elapsed time and the displayed step when it stalls, because that is what a technician needs. Tools: notepad. Time: one cycle. Step five: Power the machine down at the breaker, restore power, close the door firmly and run a short cycle without opening it. Tools: none. Time: one short cycle.
Safety first
Safety
Switch off at the breaker before removing the filter or reaching into the sump, and do not open the door on a stalled machine that is full of hot water. Unplug the appliance or switch off its breaker before removing any panel. Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. unplug-before-service
Where the owner fix ends
Call a technician when the supply valve is fully open, the hot tap runs hot, the filter is clean and the machine drains, and the cycle still stalls at the same point. That points at a fill valve, a level sensor or the control, all of which sit behind panels with mains terminals.
Nearest pages of the same kind
Generalized information
This page is generalized across the Cosmo dishwasher line. Front-control and top-control machines, and panel-ready and stainless fronts, share the ranking above but not every part, and this page does not cover a specific model or control revision. Family- and model-specific pages, where they exist, are linked below.
Links: - [Common COSMO Dishwasher Problems](/blog/cosmo-dishwasher-problems) - [COSMO Dishwasher: Abnormal Noise or Vibration](/blog/cosmo-dishwasher-abnormal-noise) - [COSMO Dishwasher: Does Not Clean or Dry](/blog/cosmo-dishwasher-cleaning-performance) - [COSMO Dishwasher: Controls, Display or Error Code](/blog/cosmo-dishwasher-control-fault)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
