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THERMADOR E3400

Thermador Dishwasher Error Code E3400: Water Fill Overfill — Variant (Extended Code)

Clear meaning, realistic next steps, and safe guidance without turning the page into a long repair manual.

What it means

Water Fill Overfill — Variant (Extended Code)

Severity

Medium - some user checks may help, but repeated faults often need service.

Can you fix it yourself?

Partial — start with DIY steps

Most likely cause

Same as E17 — overfill variant on newer models

Estimated time for safe first checks: 15–30 min.

Step-by-Step DIY Fix Guide

  1. SAFETY: Disconnect power and shut off water supply.
  2. Reset for 30 seconds. Restore and observe carefully for overfill.
  3. If overfilling, call a technician immediately.

If it's still not filling correctly

  • If normal household water flow looks good but the code returns, the inlet-valve or fill-sensing path becomes more likely.
  • If airflow still seems weak after the basic checks, the fan path or a deeper obstruction becomes more likely.
  • If the warning returns immediately after a clean restart, the sensor or wiring path becomes more likely than a one-time glitch.

What This Error Means

Error code E3400 on your Thermador dishwasher indicates: Water Fill Overfill — Variant (Extended Code). The appliance detects this condition through its built-in sensors and halts the current cycle to prevent further damage. Depending on the model, the code may flash on the display panel, appear on a digital readout, or cause the status lights to blink in a specific sequence. The dishwasher will not resume normal operation until the underlying fault is resolved.

The most frequent cause of error E3400 is same as e17 — overfill variant on newer models. When this happens, the dishwasher's control board detects the abnormal sensor reading or motor response and triggers the fault code as a protective measure. Other contributing factors are listed in the causes section below — working through them in order is the fastest path to a fix.

Many cases of error E3400 can be resolved with DIY troubleshooting — start with the steps below before calling a technician. If the steps do not clear the code, the fault is deeper in the system and professional diagnosis will be needed. The guide specifies clearly at which point to stop DIY work.

The most visible symptom of E3400 is water where it shouldn't be — either too much inside the tub, or water detected in the base tray beneath the dishwasher. Turn off the water supply valve under the sink before investigating, and lay towels around the base of the unit while troubleshooting.

Most Likely Cause by Symptom

The Thermador dishwasher may stop, pause, or refuse to complete the cycle normally.

Likely cause: Same as E17 — overfill variant on newer models

Check first: SAFETY: Disconnect power and shut off water supply.

The warning may return immediately because the appliance is detecting an internal fault.

Likely cause: Same as E17 — overfill variant on newer models

Check first: Reset for 30 seconds. Restore and observe carefully for overfill.

Common Causes

  • Same as E17 — overfill variant on newer models

What Not to Do

  • Do not run another cycle if overfilling is observed — flood risk
  • Do not leave the water supply on while diagnosing

Model and Display Variation Notes

Model-family notes

  • Thermador dishwasher display wording and code formats can vary by series.
  • If your model behaves differently, check the owner manual before trying any deeper maintenance step.

Display and panel differences

  • Panel wording can vary by series, so confirm the exact code pattern before buying parts.

Parts, Tools and Service Options

Common parts

  • Water inlet valve ($25–$60)
  • Pressure switch ($20–$45)

Manual and model check

Check your exact model and manual before ordering any Thermador dishwasher parts.

Service option

Thermador service visit if the warning returns after the basic checks are complete.

Suggestions in this section are organized to support the troubleshooting flow first. Any future affiliate relationships should be disclosed clearly.

When Not to Keep Troubleshooting

Same criteria as E17 — any observed overfilling

How to Prevent It Recurring

  • Install a leak detector tray under the dishwasher

Related Error Codes

Extra notes

  • This page is based on Thermador support material and stays conservative where model-specific guidance may vary.
  • The goal is to help you identify safe first checks before you move into parts, service, or model-specific manual lookup.

Source and model notes

Last reviewed: 2026-04-09

Based on: Based on Thermador support material and edited into consumer-safe guidance for the exact code family on this page.

View Thermador US Support

Model coverage note: Thermador dishwasher code meanings can vary by series, control panel, and model family, so use this page as a safe starting point rather than a replacement for the model-specific manual.

Important: FixThisError is an independent guide, not the manufacturer. Use your model-specific manual when the panel wording or behavior differs.

Always disconnect power before inspecting appliances. If unsure, contact a licensed appliance technician.