A tall cutting board can stop a spray arm for the whole cycle. A filter packed with rice then circulates yesterday's dinner around the tub.
Both problems are visible with the power off. Water-heating and circulation-pump faults produce similar dirty dishes but need service rather than another detergent experiment.
Before you touch it
Checks that can change the diagnosis
- Inspect the filter.
- Spin each spray arm by hand with power off.
- Look for blocked spray holes.
- Check for tall items below the racks.
- Review detergent, rinse aid and loading.
Try this in order
The safe troubleshooting sequence
Turn off power
Isolate the dishwasher before removing a filter or spray arm.
Wash the filter
Remove it according to the manual and use mild soap, running water and a soft brush.
Check spray-arm movement
Remove an arm only when the manual permits it. Rinse it and clear individual holes gently with a toothpick.
Reinstall carefully
Confirm the filter locks and each arm turns freely without hitting a rack or utensil.
Reload with space
Keep tall items away from the spray path and avoid nesting bowls or cutlery.
Use the correct products
Add fresh automatic-dishwasher detergent and refill rinse aid to the marked level.
How you know the simple fix worked
Both racks should receive water and food residue should clear during the appropriate cycle. Persistent cold water or loud circulation noise needs diagnosis.
Technician territory
Stop the job when you see any of these
- The dishwasher does not fill
- Water remains cold
- A returning error code
- An unusually loud circulation pump or broken mounting parts
The claim can change the repair decision
Maintenance, a warrantyWritten warrantyA written promise supplied with the appliance sale. Federal law treats it as part of the product bargain rather than a separate paid plan. and a service contractService contractA separately purchased agreement that pays for stated maintenance or repair during a fixed period. Sales pages often call it an extended warranty. are different things.
Filters and loading are owner maintenance. A circulation pump or heater may fall under cover, so keep notes from a test cycle after the accessible parts are clean. Federal warranty protections do not make every DIY mistake covered, and a paid service contract may require authorization before a part is replaced.
Common questions
The short answers
Can I clear spray holes with wire?
Use only the gentle method the manufacturer recommends. A wooden toothpick is commonly suggested because it is less likely to enlarge an opening.
Why is only the top rack dirty?
A blocked or stationary upper spray arm is one possibility. A circulation or diverter fault can create the same pattern and needs service.
Instructions checked against primary sources
Official guidance used for this fix
- BoschOfficial poor-cleaning troubleshooting
- BoschCleaning a dishwasher filter
- Federal Trade CommissionWarranty restrictions and damage caused by independent repair
Guide reviewed August 2026. Model construction varies. The owner manual and recall notices for the exact model take priority over a general guide.