AEG AX91-604 Error Code Filter not recognized: Meaning, Fixes & Troubleshooting

AEG AX91-604 Error Code Filter not recognized means the AEG Wellbeing app or the purifier’s firmware cannot detect or verify the filter currently installed. This can happen if the filter is not seated correctly, if the sensor or connector is dirty, if a non‑original or incompatible filter is fitted, or if the purifier and app lost communication.

• App shows the message “Filter not recognized” or similar error on the device page.
• The purifier may show an alert icon or a flashing indicator related to filter status.
• The purifier runs but the app does not allow filter-related functions (reset counter, view life).

• Filter not fully inserted or retaining clips not engaged.
• Protective packaging or sticker left on the new filter.
• Dirty or misaligned filter sensor/contact inside the purifier.
• Incompatible or third‑party filter lacking the expected identifier.

1. 1
   Power off and unplug the purifier. Remove the filter and inspect the sensor area (near filter seat) for dust or fibres; gently clean with a dry, lint‑free cloth. Reinstall the filter and test.
2. 2
   Confirm there is no protective film, bag, or sticker on the filter’s connection surface. Remove any packaging and reseat the filter.
3. 3
   Try a known good/original AEG filter if available (AEG part numbers shown on accessory pages). If the error disappears with a genuine filter, the previous filter may be incompatible.
4. 4
   Reset the purifier in the app: remove the device from the AEG Wellbeing app (if safe to do so), then re-add it following normal onboarding steps, or contact AEG support for guidance before factory reset.

• Leaving transport plastic or protective stickers on the new filter.
• Not seating the filter fully so the sensor cannot detect it.
• Using a visually similar but incompatible third‑party filter.

• Do not use liquids or compressed air directly on sensors—this can damage electronics.
• Do not force connectors or parts—avoid applying excessive force when reseating the filter.

• Always power off and unplug the unit before removing the filter or cleaning inside the purifier.
• If you smell burning or see smoke, stop use immediately and contact AEG support or qualified service.

Contact AEG support if the error persists after reseating the filter, testing a genuine filter, cleaning the sensor area, and restarting both the purifier and the AEG Wellbeing app. If the purifier won’t power normally, shows other error codes, or if you suspect a hardware fault, arrange service through AEG.

• Always remove packaging and stickers from replacement filters before installing.
• Use genuine AEG replacement filters recommended for AX91-604 when possible.
• Keep the filter seating area clean and check filter fit during routine maintenance (every 1–3 months depending on environment).