Dishwasher shows E20; may not circulate water properly or may be noisy.

Safety: Turn off power and water. Expect some residual water when opening the base.

E20 points to a problem with the main wash circulation pump.

• Listen to pump: During a wash cycle, if you hear only a humming noise and no strong spray, the pump may be jammed.
• Access pump: Remove the base panel and locate the circulation pump attached to the sump.
• Check for obstructions: Disconnect the pump and inspect the impeller area for glass, bones, or other debris. Remove any foreign objects.
• Spin test: Rotate the impeller by hand; it should move smoothly. If stiff or seized, the pump is likely faulty.
• Electrical test: Measure the motor winding resistance and compare with specifications. An open or shorted winding indicates failure.
• Replace pump: If the pump is worn or seized, replace the Neff circulation pump assembly.