AEG L fault codewhat it means and how to fix it
The panel is locked, and AEG publish two different locks that both show L. One re-arms itself every time you switch off, which is why hobs seem to lock themselves.
Before you start
What L means
L is the lock, and the reason this deserves a page rather than a line is that AEG document two separate functions that both display it, with different sequences and different behaviour. Getting the wrong one is why people conclude the hob is faulty. The Lock function locks the panel while you are cooking, so a sleeve or a boiling-over pan cannot change the heat setting. You select a heat level first, then touch the key; L lights for four seconds and the timer carries on running. It is a temporary guard over a session in progress.
The Child Safety lock locks the panel when you are not cooking, and it is the one that causes the complaints. You activate the hob without setting a heat level, hold the key for four seconds, and L comes on; then you deactivate the hob. To turn it off you repeat the sequence and a zero appears.
The important part is the override: you can activate the hob, see the L, hold the key for four seconds and set a heat setting within ten seconds, and the hob will work for that session — but the lock re-arms as soon as the hob is switched off. That single behaviour accounts for almost every report of a hob that keeps locking itself. The owner has found the override, used it, and reasonably assumed they turned the lock off. They did not. They suspended it for one session, and it came back exactly as designed. Turning it off properly needs the full deactivation sequence, and the confirmation is the zero on the display.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Child Safety lock is armed | The one behind most complaints. It re-arms every time the hob is switched off, so a session override does not clear it and it appears to lock itself repeatedly. | Common |
| The Lock function was touched during cooking | A guard over a session in progress. It is easy to catch the key with a hand or a cloth while cooking. | Common |
| A spill or object holding the key down | AEG document liquid and objects on the panel triggering behaviour of their own, and a wet panel can register a long touch on the lock key. | Occasional |
What to try yourself
Work out which lock you have. If you can override it for one session and it comes back next time, it is the Child Safety lock rather than the Lock function.
For the Lock function, touch the key again. The L clears and the setting you were on is still there.
To turn the Child Safety lock off properly, activate the hob without setting a heat level, hold the key for four seconds, and look for a zero on the display. That zero is the confirmation.
To use the hob once without turning the lock off, activate it, wait for the L, hold the key for four seconds and set a heat setting within ten seconds.
Wipe and dry the control panel. A wet panel can register touches you did not make, including on the lock key.
Get a qualified appliance engineer to look at your AEG L
We do not pass enquiries to a repair firm, so there is no form here. When you book a qualified appliance engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
What it costs to fix
Typical repair cost
£0
Time on site
5 minutes
Nothing. This is a function you can turn on and off from the panel.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Own this appliance and had this code? . Nothing is published until a person has read it.
Related AEG fault codes
- Flashing between two numbersUsually simple to fixPower management, not a malfunction. Two zones on one side share a supply, and the display is showing you what you asked for and what you are getting.Related: settings and modes
- FUsually simple to fixOn an induction hob this is about the pan, and AEG say whether it is steady or flashing changes the answer. Steady on a new hob means the installation.Related: same brand
- E4Usually simple to fixOverheating protection operating, not a breakdown. It clears itself as the hob cools, and AEG warn that the residual heat H may stay on afterwards.Related: same brand
- Burner will not stay alightGet it checkedThe flame dies when you let go of the knob. AEG give two causes and only one is yours: a dirty or misplaced burner cap, or a failed thermocouple.Related: same brand
- E3Get it checkedThe hob is seeing 400 volts. AEG name the person to ring and it is not their service line — it is the qualified electrician who installed it.Related: same brand
- E8Get it checkedAsk one question first: has this hob ever worked? A new install means a missing phase in the wiring. A hob that worked and stopped means the electronics.Related: same brand
Own an AEG hob? Save it and its codes come first next time.
Related guides
Common questions about AEG L
Why does my hob keep locking itself?
Almost certainly because you are using the single-session override on the Child Safety lock rather than turning it off. AEG document that the lock re-arms when the hob is switched off, so the override gets you through one session and the L is back the next time. The full deactivation sequence is different and it confirms with a zero on the display.
What is the difference between the two locks?
The Lock function locks the panel during cooking, after you have set a heat level, so the setting cannot be nudged. The Child Safety lock locks the panel when the hob is not in use, is armed without setting a heat level, and stays armed across sessions.
How do I know the child lock is really off?
AEG publish the confirmation: a zero appears on the display when the Child Safety lock is deactivated. If you did not see a zero, it is still armed.
My hob has a colour touchscreen and no lock key. Where is it?
AEG say the methods differ by model, and that on hobs with a touchscreen the child lock is set and cleared through the menu rather than by holding a key. The four-second and ten-second timings on this page are for the touch-control panels with a padlock key; on a touchscreen hob, follow the menu path in the user manual.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer support portal
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.