What E4 means on your Bosch vent hood
Error code E4 is a maintenance reminder rather than a fault — it indicates that the grease filter needs cleaning or replacement. Bosch vent hoods track runtime hours and trigger E4 when the accumulated operating time reaches a preset threshold (typically 30–50 hours of fan operation). Some models also have an optical sensor that detects grease saturation.
Symptoms
- E4 indicator illuminates on the control panel
- The vent hood still functions normally
- You may notice reduced suction due to a saturated filter
- More grease residue on the cooking surface and surrounding areas
Common causes
- Normal runtime accumulation — the timer has reached the cleaning threshold
- Grease-saturated filters — the metal mesh or baffle filters have accumulated grease and need cleaning
Troubleshooting steps you can try
- Remove and clean the filters — take out the metal grease filters and soak them in hot water with a degreasing dish soap for 15–20 minutes. Scrub gently and rinse. Most Bosch vent hood filters are also dishwasher-safe — run them on the bottom rack with a hot cycle.
- Replace charcoal filters — if your hood uses recirculation mode with charcoal filters, replace them. Charcoal filters cannot be cleaned and should be replaced every 3–6 months.
- Reset the indicator — after cleaning/replacing filters, press and hold the filter reset button for 3–5 seconds (varies by model). The E4 indicator should turn off.
When to call a technician
E4 doesn’t require a technician. It’s a maintenance reminder that you can resolve by cleaning or replacing the filters and resetting the indicator. If E4 won’t reset after holding the button, consult your model’s manual for the specific reset procedure — some models require a specific button combination. Codes may vary by model generation and series.
Need help? Schedule Bosch Vent Hood repair with a certified technician, or contact our team for a free diagnosis consultation.
