Dishwasher runs drain pump continuously and will not advance through cycle; may show C1 on display and beep.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety first: Disconnect power at the breaker and turn off the water supply before working on the dishwasher. Use towels to catch any residual water.
- Check the sink drain and garbage disposer: Ensure the sink drains freely. If recently installed or replaced, confirm the disposer knockout plug was removed from the dishwasher inlet.
- Inspect the air gap (if installed on countertop): Remove the air gap cap and clean out any food debris or grease blocking the outlet or inlet tubes.
- Clean the sump and filter area: Remove the lower rack and spray arm. Lift out the fine and coarse filters in the bottom of the tub. Rinse under warm water and remove any food, glass, or labels from the sump opening where water drains.
- Check the drain hose routing: Verify the hose is not kinked behind the dishwasher or under the sink. Ensure it has a proper high loop or connects to an air gap to prevent backflow.
- Test the drain pump: With power still off, access the bottom front of the dishwasher (remove toe kick). Locate the drain pump on the side of the sump. Check for obstructions in the pump inlet and impeller. If the impeller is damaged or the pump hums but does not move water when powered, the pump likely needs replacement.
- Reset the control: Restore power, then cancel the cycle and start a short cycle to see if the error clears after obstructions are removed.
If the C1 error persists after clearing all blockages, the drain pump or control board may be faulty and should be tested or replaced by a qualified technician.