- Clean the accessible filter and remove trapped debris from the drain area.
- Check the drain hose or outlet path for kinks, crushing, or blockages.
- Run a short cycle and confirm the appliance empties fully.
Drain/pump-out fault. On the Kuppersbusch IGV 645.0, this code relates to the dishwasher and should be interpreted together with how the appliance is behaving right now.
- The dishwasher displays F4 instead of normal status information.
- The current cycle, function, or startup sequence may stop, pause, or behave differently than expected.
- The same code may return after a reset if the underlying issue is still present.
- Drain filter, sump, or outlet path is blocked.
- Drain hose is kinked, crushed, or blocked, or the pump cannot clear the water properly.
- Check whether the fault started after installation or after reconnecting the drain line.
- Make sure the waste connection is open and routed correctly.
- If the code returns after clearing the drain path, the pump or related control circuit may need service.
- Isolate power before reaching into pump or filter areas.
Book service if F4 returns after cleaning the drain path, or if the pump sounds abnormal and the dishwasher still cannot empty correctly.
Can F4 clear after a reset?
Sometimes a temporary glitch clears after one full reset, but a repeated return usually means the same underlying issue is still there.
Should I keep using the appliance if it works again briefly?
Only if the code stays away and the appliance behaves normally. If the same code comes back, stop and move to service or more targeted diagnosis.