Bosch Dishwasher Error Code E18

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

1. Power off and isolate water: Turn off and unplug the dishwasher or switch off the breaker and shut off the water supply before inspecting.
2. Remove visible water: Use a cup or towels to remove standing water so you can inspect the filter and sump area safely.
3. Clean the filter assembly: Remove and clean the coarse and fine filters, rinse under running water to remove debris and grease.
4. Inspect the sump and filter housing: Look for bits of glass, food, labels or foreign objects that can jam the pump impeller.
5. 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.
6. 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.
7. 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.
8. Reset the dishwasher: After clearing blockages, restore power and run a short drain/quick cycle to confirm the error is cleared.
9. Run a diagnostic/service mode: If your model supports it, run the diagnostic to check pump operation and error history.
10. Test the pump electrically: With power safely isolated, you can test pump motor continuity with a multimeter. If the pump shows open circuit or fails to run when powered in a controlled test, it likely needs replacement.
11. Replace defective parts: If cleaning and hose checks don’t fix E18, replace the drain pump, check valve, or control board as diagnostics indicate.
12. Call a professional: If you’re not comfortable opening panels or testing electrical components, contact Bosch service or a qualified appliance technician.

Maintenance / Prevention Tips

• Empty and rinse large food scraps from dishes before loading to reduce debris entering the filter.
• Clean the dishwasher filter weekly or after heavy use to prevent buildup.
• Inspect the sump area monthly for small foreign objects or glass shards.
• Run a monthly maintenance cycle with a dishwasher cleaner to remove grease and limescale.
• Flush or run water through the drain hose periodically to avoid sediment buildup.
• Ensure the drain hose is free of kinks and has a proper high loop or air gap per installation instructions.
• After garbage disposal replacement, verify the dishwasher knockout plug was removed and install correctly.
• Avoid using oversized food particles and starchy foods that can swell and block filters.
• Use the correct detergent and avoid overuse which can cause residue and clogs.
• Check and clean the spray arms occasionally to prevent debris circulation to the pump area.
• Keep door seals clean and free of debris that could fall into the sump space.
• If you have hard water, consider a water softener or descaler to reduce limescale in the pump and hoses.
• Inspect the installation periodically to ensure the drain hose routing hasn’t shifted or become pinched.
• Replace aged hoses that show wear, soft spots, or internal collapse signs.
• Use a strainer or sink trap maintenance to prevent household debris from backing up into the dishwasher drain.
• Check the non-return/check valve for proper operation during routine maintenance checks.
• When moving or servicing the dishwasher, take care not to bend or trap the drain hose.
• Address small leaks or strange noises promptly before they escalate into pump faults.
• Follow Bosch’s recommended service intervals and use authorized parts for repairs.

FAQs

Q: Can I ignore the E18 error and keep using the dishwasher?

A: No. Ignoring E18 can lead to standing water, odors, bacterial growth, and possible leaks. The dishwasher may not complete cycles and continuing to run it can cause further damage to the pump or electronics.

Q: Is E18 an expensive repair?

A: Costs vary. If the problem is a simple clog, there’s no parts cost — just your time. If the drain pump needs replacement, expect a moderate repair cost for parts and labor. If the control board is at fault, the cost can be higher. Local labor rates and model specifics influence price.

Q: How do I reset the Bosch dishwasher after clearing a clog?

A: Many Bosch models reset by turning the dishwasher off and on at the power for a minute or selecting the reset/program cancel option in the control panel. Consult your model manual for the exact reset procedure.

Q: Can I replace the drain pump myself?

A: If you’re comfortable with basic appliance disassembly and electrical safety, you can replace the drain pump following the service manual. Always isolate power first. If not confident, hire a trained technician.

Q: My dishwasher shows E18 intermittently — what does that mean?

A: Intermittent E18 often points to partial clogs, debris moving in and out of the pump, or an intermittently failing pump motor. Regular cleaning usually helps; persistent intermittent faults suggest a failing pump or electrical/connectivity issue.

Conclusion & Safety Notice

Address the Bosch E18 error promptly to avoid odors, standing water, and possible damage. Basic checks like cleaning the filter, clearing the sump, and inspecting the drain hose often resolve the issue. However, working on the pump and electrical components carries risk — always disconnect power and water first. If the problem persists after basic troubleshooting, or if you’re unsure how to safely access internal parts, contact Bosch customer service or a qualified appliance repair technician. Professional repair is recommended when the drain pump needs replacement, the control board may be faulty, or when the appliance is still under warranty.

If you choose DIY repair: wear gloves, use proper tools, follow the service manual, and stop if you encounter unclear wiring or signs of electrical damage. For most users, calling a certified technician ensures a safe, reliable repair and protects warranty coverage.