What this error means
Drainage issue — the drain pump is running but water is not leaving the machine quickly enough.
The E21 error on an AEG washing machine indicates the machine has detected that drainage is occurring too slowly — the pump is running but water is not being removed at the rate the control board expects. This is a flow rate fault rather than a complete drainage failure. The most common causes are a partially blocked pump filter, a drain hose that is incorrectly positioned or partially kinked, a household standpipe or sink waste that is beginning to block, or a pump impeller that is partially obstructed. A pump motor that is running but losing efficiency due to wear will also produce E21.
What you'll need first
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Step-by-step
Symptoms to look for
- Machine takes noticeably longer to drain than it used to
- Pump sound continues for longer than expected during drain and spin phases
- Water drains but very slowly — some water remains in the drum at the end of a programme
- E21 appears at the end of a wash or rinse cycle
How to fix it
Unplug the machine from the mains completely. Lay towels across the floor in front of the machine and place a shallow tray beneath the filter access flap. Even though E21 indicates slow drainage rather than no drainage, water will still be present in the drum and hose.
Open the access flap and position your tray beneath the filter cap. Turn the cap anti-clockwise by a quarter turn to begin releasing water slowly into the tray. Empty the tray, then continue unscrewing until the cap comes free. Pull the filter out fully. Rinse it under warm running water, scrubbing the mesh with a toothbrush to remove all lint, hair, fabric fibres, and debris. Reach into the filter housing cavity with a torch and clear any debris from around the pump entrance.
Shine a torch into the empty filter cavity and locate the impeller at the rear. Rotate it gently with one finger. It should spin with smooth, even resistance through a full rotation. Any catching, grinding, or intermittent stiffness in one position indicates a partial obstruction around the impeller blades.
Trace the drain hose from the machine to the standpipe or sink waste connection. Straighten every kink, sharp bend, and compressed section along its full length. Confirm the hose end is inserted no more than 15 centimetres into the standpipe, is not sealed against the pipe walls, and that the hose has an upward loop reaching at least 60 centimetres above floor level before descending to the waste connection.
With the machine unplugged, remove the rear lower access panel if fitted. Inspect the short rubber hose between the pump outlet and the main drain hose for any collapse, kinking, or compression that would restrict the flow path out of the pump.
When to call an engineer
- Pump impeller turns but only with significant stiffness — partial blockage inside the pump body that cannot be cleared from the filter side
- E21 persists after filter cleaning, hose inspection, and household drain check — pump motor losing efficiency and requires replacement
- Pump outlet hose has collapsed internally and cannot be straightened
- Wiring to the pump is damaged or the connector is corroded
Frequently asked questions
What is the difference between E20 and E21 on an AEG washing machine?
Can a partially blocked household drain cause E21?
Does E21 mean my pump is failing?
How often should I clean the AEG pump filter to prevent E21?
🎯 What is likely causing this fault?
⚠️ Estimates based on common faults — not a guaranteed diagnosis. Always verify before ordering parts.
Parts you may need
Enter your model number to filter results to your exact machine
Usually found on a label inside the door frame or on the back panel of the machine.
| Part | Approx. UK Cost | Find it |
|---|---|---|
| Drain Pump | £15 - £30 | 🛒 Amazon UK → |
| Drain Pump | £15 - £30 | 🏷️ eBay UK → |
ℹ️ Prices are approximate. Always check the part number matches your model before ordering. Not sure of your model number? Find out how to locate it here.