Dishwasher makes a high-pitched whining noise during wash or drain.

Safety: Disconnect power before accessing pumps.

• Check water level: Ensure the dishwasher is filling to the correct level; low water can cause pump cavitation and whining.
• Clean filters and sump: Remove all filters and clean the sump to ensure good flow to the pump.
• Isolate which pump: Listen carefully to determine if the noise occurs during wash (circulation pump) or drain (drain pump).
• Inspect pump: Access the noisy pump and check for play in the shaft or signs of leakage. If bearings are worn, replace the corresponding Neff circulation pump or drain pump.