E31 — Turbidity sensor fault
E31 is not in Bosch's official US dishwasher error-code list (which covers E01-E27, E0100-series, and E2000/E3000/E6000/E8000/E9000-series codes, but not a bare E31). The 'turbidity sensor fault' explanation below is not confirmed by Bosch's US consumer page — verify against your model's manual before assuming this specific cause.
- Keep using it?
- Yes, with caution
- DIY difficulty
- Hard
- Verified against
- bosch-home.com ↗
How to fix it
- Run a hot Rinse cycle with a cup of white vinegar in the tub to clean optics.
- If still failing, remove the dishwasher and access the sump from below.
- Disconnect the turbidity sensor and clean the optical lens with a soft cloth.
- Reseat the harness connector.
- If the error persists after cleaning, replace the turbidity sensor.
Why it happens
Typical signs: Auto program errors or won't run · Cycle defaults to longer fixed time · E31 with otherwise normal operation
- Soiled sensor optics Limescale or grease coating the optical window.
- Failed turbidity sensor LED or photodiode in sensor has failed.
- Sensor harness fault Broken or disconnected harness to the sensor.
- Control board input fault Rare PCB-side input failure.
Parts you may need
If diagnosis points to a failed part, these are the common replacements. As an Amazon Associate we earn from qualifying purchases.
- Bosch dishwasher turbidity sensor Common replacementAmazon →
More Bosch dishwasher codes
Always unplug an appliance before servicing it. This guide is for informational purposes and is not a substitute for a qualified technician. Verified against manufacturer documentation: bosch-home.com.