Dishwasher stops and displays i50; may not circulate or drain water; sometimes accompanied by humming from the bottom.

Safety first: Turn off power at the breaker before accessing the base of the dishwasher.

• Listen for pump operation: Start a cycle and listen (briefly, with panels on) to determine if the circulation pump runs at all. Then disconnect power.
• Inspect wiring: Remove the lower access panel and check the wiring harness to the circulation and drain pumps for burns, loose connectors, or damage.
• Check for obstructions: Remove the circulation pump from the sump (if accessible) and inspect the impeller for broken pieces or foreign objects.
• Test and replace components: Using a multimeter, check pump windings for continuity. If open or shorted, replace the pump. If pumps test good but i50 persists, the main control board relay is likely faulty and the board should be replaced.

Because this involves electrical testing and board replacement, many homeowners prefer to have a technician perform this repair.