Dishwasher runs for a very long time, then stops and may beep; display shows C1.

Safety first: Turn off power at the breaker and shut off the water supply before working on the dishwasher. Use towels to catch any water spills.

• Check and clean the filters: Remove the lower rack. Twist and lift out the fine and coarse filters from the sump. Rinse under hot water and remove food debris. Reinstall securely.
• Inspect the drain hose: Pull the dishwasher slightly out if needed. Locate the drain hose where it connects to the garbage disposal or sink drain. Remove the clamp and hose, then check for clogs (seeds, glass, food). Flush with hot water. Ensure there are no kinks or sharp bends.
• Check the air gap (if installed): Remove the air gap cap on the sink. Clear any debris inside with a small brush and hot water.
• Test the drain pump: With power still off, access the bottom front of the dishwasher (remove toe-kick panel). Locate the drain pump on the sump. Check for obstructions in the impeller by removing the pump (usually held by a twist-lock or a few screws). If the impeller is damaged or the pump is noisy or seized, it should be replaced.
• Restore power and test: Turn the breaker back on, run a short cycle, and observe the drain performance. If C1 returns after cleaning and hose checks, the drain pump is likely weak and needs replacement.