What this error means
Door lock fault — the washing machine cannot confirm the door is securely closed and locked.
The E40 error on an AEG washing machine means the machine cannot verify that the door is fully closed and the door interlock is engaged. AEG machines check door lock status before and throughout every programme as a safety measure — the drum must never rotate with an open or unsecured door. The most common causes are the door not being pushed fully shut, an item of laundry or debris trapped in the door seal preventing full closure, a worn or damaged door latch, a faulty door interlock switch, or a worn door hinge causing the door to sag out of alignment with the catch plate.
Step-by-step
Symptoms to look for
- Door will not lock at the start of a new programme
- Machine starts then stops immediately with E40 on the display
- Cycle pauses mid-wash with a door fault displayed
- Door appears fully closed visually but the programme will not begin
How to fix it
Press the door firmly with both hands placed on the outer plastic frame, one on each side of the glass — never apply pressure directly to the glass panel. You should feel and hear a solid click as the latch hook engages in the catch plate. Once closed, the door face should sit completely flush with the front panel of the machine with no gap visible around the edge.
Open the door fully and run your fingers slowly around the entire rubber gasket seal, pressing your fingertips firmly into each fold. Work around the full circumference including the lower section which accumulates the most debris. Remove any clothing, coins, hair grips, or solid material you find.
Open the door and look closely at the plastic latch hook on the door edge — it must be completely intact with no cracks, chips, or deformation. Now look into the catch plate slot on the machine body that the hook enters. Both must be undamaged, clean, and correctly aligned with each other.
With the machine unplugged, look into the catch plate opening on the machine front panel. The door interlock switch is the small mechanism visible inside the slot. Check it is not physically obstructed, discoloured, or showing any signs of burning, melting, or mechanical damage.
Open the door to its full extent and examine the top and bottom hinge points on both the machine body and the door edge. Apply gentle upward pressure on the outer edge of the open door and observe whether it lifts noticeably. Visible lifting indicates worn hinge bushings. A door that sags will misalign with the catch plate and cause intermittent E40 faults that worsen over time.
Unplug the machine from the mains and hold the power button down for five seconds to discharge the control board. Leave unplugged for a full 60 seconds. Plug back in and start a short programme.
When to call an engineer
- Door interlock switch fails a continuity test using a multimeter — switch must be replaced
- Door latch hook is visibly cracked, chipped, bent, or broken away
- Door sags noticeably on one side — hinge is worn, seized, or damaged
- Wiring to the door interlock is burnt, chafed through, or the connector has melted
Frequently asked questions
Is E40 dangerous?
Why does E40 appear during a cycle but not consistently when starting?
Will the machine drain before the door lock releases after an E40 fault?
Can a worn door hinge cause E40?
🎯 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 |
|---|---|---|
| Door Lock Assembly | £20-£45 | 🛒 Amazon UK → |
| Door Lock Assembly | £20-£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.