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Dishwasher Circulation (wash) pump: What It Does and Signs It's Failing

The main wash motor and pump, mounted to the sump housing in the bottom of the machine. It pulls water from the bottom of the tub and forces it up through the spray arms again and again during washing and rinsing. Bosch builds the water heater into this pump housing, which is why its codes call the part a 'heat pump'. The sump seal is the rubber gasket that seals the pump to the sump housing.

How it works

A motor turns an impeller that pressurizes water from the sump and sends it to the spray arms, while the filter catches food before it reaches the pump. Most machines empty the tub with a separate drain pump, though some run a drain impeller off the same motor.

Signs it is failing

• Dishes come out dirty even with clean filters and spray arms
• Loud grinding or rattling during the wash, not just at drain time
• Cycles that run much longer than they used to
• A puddle under the front of the machine from a worn pump or sump seal
• Heating or 'pump blocked' codes on models that combine the heater with the pump

Wash motor codes, Bosch's 'heat pump blocked' and limescale codes, and some leak codes trace back to this assembly. Miele notes that a machine left unused for weeks or months can have a pump that dried out and stuck.

Can you replace it yourself?

You can check the easy stuff yourself with the power off: clean the filters, clear the spray arm holes and look for broken glass in the sump. Swapping the pump means shutting off water and power, disconnecting the supply and drain, pulling the machine out and laying it on its back, and getting the sump seals right so they don't leak. Parts sites sell it as a DIY job, but it's a long one, and most owners are better off calling a tech.

Buying the right part

Circulation pumps are model-specific and often sold as a kit with the motor, seal and mounting ring. Buy OEM by full model number; a mismatched seal leaks.

Error codes linked to the circulation (wash) pump

• E15Water detected in the base (leak protection)Bosch
• E09Heating fault (meaning varies by region)Bosch
• E12Limescale buildup in the heat pumpBosch
• E21Heat pump blockedBosch
• i50Drain or wash motor problemFrigidaire
• F7E2Wash motor errorKitchenAid
• FAE5 / F10E5Diverter leakKitchenAid
• LE / CEWash motor problemLG
• F14Circulation pump stuck or water level faultMiele
• F78Circulation pump blockedMiele
• 3CWash pump errorSamsung
• 3EIncoming water too hot (US) or pump error (UK/AU)Samsung
• F7E2Wash motor errorWhirlpool

Last reviewed 2026-10-19.