Bosch Dishwasher E18 Error — What It Means
The Bosch E18 error code indicates a drainage problem: the dishwasher cannot pump out water properly. When your Bosch displays E18 it usually means the drain pump, drain hose, filter area, or associated components are blocked, jammed, or failing. This prevents normal water removal at the end of a cycle and can stop the dishwasher from completing programs. Common user impacts include standing water in the tub, longer or stalled cycles as the machine repeatedly attempts to drain, poor rinse and drying performance, increased risk of lingering odors and bacterial growth, and in some cases a higher chance of leaks or electrical faults if water reaches sensitive parts. Addressing E18 promptly reduces the chance of damage to the appliance and your kitchen floor.
Common Causes
- Clogged or dirty filter and sump area (food debris, glass, scale)
- Foreign objects trapped in the drain pump impeller (bones, glass, labels)
- Kinked, crushed, or blocked drain hose
- Blocked or clogged sink trap/garbage disposal connection or air gap
- Faulty or seized drain pump motor
- Stuck or damaged check valve/non-return valve
- Electrical or control board fault preventing pump activation
- Incorrect installation height or plumbing (siphon issues)
Troubleshooting Steps
- Power off and isolate water: Turn off and unplug the dishwasher or switch off the breaker and shut off the water supply before inspecting.
- Remove visible water: Use a cup or towels to remove standing water so you can inspect the filter and sump area safely.
- Clean the filter assembly: Remove and clean the coarse and fine filters, rinse under running water to remove debris and grease.
- Inspect the sump and filter housing: Look for bits of glass, food, labels or foreign objects that can jam the pump impeller.
- Access and check the drain pump impeller: Remove the lower spray arm and access panel (consult your manual), then visually check the pump impeller for obstructions or damage. Clear debris if present.
- Check the drain hose: Inspect the hose for kinks, clogs, or creases. Disconnect and flush the hose with water. Make sure the hose is routed correctly with a high loop or air gap.
- Check sink trap and garbage disposal: If the dishwasher drains into a disposal, ensure the knockout plug was removed during installation and the trap is not blocked.
- Reset the dishwasher: After clearing blockages, restore power and run a short drain/quick cycle to confirm the error is cleared.
- Run a diagnostic/service mode: If your model supports it, run the diagnostic to check pump operation and error history.
- Test the pump electrically: With power safely isolated, you can test pump motor continuity with a multimeter. If