What you are most likely looking at
The useful question is when the noise happens: during the fill, during the wash, or during the drain. Each stage has its own short list. That puts hard debris in the sump or filter at the top of the list here and water hammer at the inlet valve at the bottom.
What you observe
- A grinding or rattling during the wash — Something hard in the sump, or a spray arm striking the load.
- A hum without water movement — A pump running against a blockage or a jammed impeller.
- NEAR MISS — the machine is quiet but leaves dishes dirty — That is a cleaning question, not a noise one.
The causes, ordered
- Hard debris in the sump or filter — A fruit stone, a shard of glass or a bottle cap in the sump rattles against the impeller every time the pump runs. It sits at the top because it costs nothing to check and it is right often enough to check first every time.
- The load fouling a spray arm — A tall item, a pan handle or a fallen utensil stops or clips the arm, and it is corrected without tools. How the machine is loaded produces symptoms that read exactly like failures, so habits are checked before parts.
- A spray arm bearing or mount worn — An arm that wobbles rather than spinning true makes a repeating knock. Plumbed premium units carry a filter, a valve and a long internal tube run, every one of which is a candidate the moment water appears.
- Water hammer at the inlet valve — A bang in the pipes when the valve closes; it is the plumbing that needs the arrestor, not the machine.
Where to start, and what each check rules out
- Note which stage the noise belongs to — Fill, wash and drain each have their own candidates.
- Pull the filter and feel around the sump with a cloth — Hard debris is the commonest finding, and it is why a cloth is used rather than fingers.
- Spin both spray arms and watch for contact with the load — An arm that hits a pan handle sounds far worse than it is.
- Press a hand on the worktop above the machine while it runs — If the sound dampens, the machine is not fixed into the cabinet.
What to try yourself
- Clear the filter and the sump — Use a torch and a cloth; assume any hard object found is the answer.
Tools: torch, cloth
- Check the fixing brackets that hold the machine to the worktop or cabinet — A loose machine transmits its noise into the kitchen.
Tools: screwdriver
- STOP before removing the sump, the pump or the wash motor — Mains wiring, sharp debris and a plumbed machine.
Power, panels and what not to do
Safety
Assume broken glass in any sump: use a torch and a cloth rather than bare fingers. Cut power at the breaker before reaching below the filter, and remember a capacitor can hold a charge after the power is off.
Where the owner side ends
Sump debris, loading and cabinet fixings are yours. Pumps, motors and arm bearings are service work, and a grinding noise with poor cleaning should not be run for weeks.
Nearest pages of this class
Generalized information — and what is missing from it
Generalized information: this describes the dishwasher class, not your serial number. Anything tied to a chassis — pinouts, part numbers, diagnostic key sequences — is absent by design. A family- or model-level page, where one exists, is linked below and takes precedence. The brand overview page linked below covers the other problems on this machine.
Links: - [Common Café Dishwasher Problems](/blog/caf-dishwasher-problems) - [Café Dishwasher: Does Not Clean or Dry](/blog/caf-dishwasher-cleaning-performance)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
