AEG AX91-404 Error Code Air purifier LED (white dot) or alert icon flashes repeatedly: Meaning, Fixes & Troubleshooting

AEG AX91-404 error code Air purifier LED (white dot) or alert icon flashes repeatedly indicates the purifier has detected a fault condition or operating state where it cannot run normally. Common causes include a blocked or incorrectly seated filter, insufficient airflow, or an internal sensor reporting an issue. Follow the fixes and checks below to confirm and resolve the problem safely.

• White LED dot or alert icon on the control panel flashes repeatedly instead of normal status lights.
• Purifier stops running, runs briefly, or runs at reduced power while the alert flashes.
• Airflow feels weak or the fan does not start despite power being on.

• Blocked, dirty or mis-seated filter causing airflow or sensor errors.
• Unit placed too close to walls or obstructions, restricting intake/outlet airflow.
• Temporary electronic glitch that needs a power cycle or reset.
• A sensor or internal component is failing (less common).

1. 1
   Remove the pre-filter and main filter(s). Look for heavy dust, pet hair, or debris. If visibly clogged, replace filters following AEG guidelines. Do not wash filters unless the manual explicitly allows it.
2. 2
   Using a soft brush or dry cloth, gently remove dust from vents and the sensor openings visible in the filter compartment. Do not insert objects into sensors.
3. 3
   With filters reseated and vents clear, power off, unplug for 60 seconds, plug in and power on while watching the LED pattern. Note whether the alert returns immediately or after some minutes.
4. 4
   Move the purifier to a different room or position to rule out environment-related airflow obstructions or extreme dust sources.
5. 5
   If the alert recurs, note how long after startup and under what conditions (e.g., fan speed changes, after heavy dust removal). This information helps support diagnose if you contact AEG.

• Assuming the filter is fine without inspecting it closely for hair or compacted dust.
• Placing the unit too near walls, curtains or furniture which restricts airflow.
• Using water or liquids on non-washable filters or inside the unit.

• Do not insert objects into sensor openings or vents to try to ‘fix’ a sensor reading.
• Do not wash or soak filters unless the user manual explicitly states they are washable—doing so can damage the filter and electronics.

• Always unplug the purifier before opening the filter compartment or performing maintenance.
• Do not attempt repairs beyond visual checks and part replacement. Internal electrical work should be done by authorised technicians.

Contact AEG support if the alert continues after you have completed the Fix it fast steps and deep checks, if the unit does not power up, or if you suspect a sensor or motor failure. Provide the model (AX91-404), a description of the LED/alert behaviour, and the troubleshooting steps you already tried. If the unit is under warranty, have purchase details ready.

• Replace filters on the schedule recommended in the user manual and keep spare filters on hand.
• Keep the intake and outlet vents clear—maintain at least 30 cm of space around the purifier.
• Perform a quick visual filter check every 1–3 months and clean visible dust from the unit exterior.