- Switch the oven off, allow it to cool if needed, and isolate power for 60 seconds.
- Check for any obvious recent power interruption and remove power for 60 seconds before restarting the oven.
- Restore power and check whether F109 clears. If it does not, move to the deeper checks below.
Listed as a fault code that requires a service call-out. On the AEG TP8SB73WAT, a persistent F109 usually means the related component, connection, or control path needs further diagnosis.
- F109 appears on the display and normal oven operation is interrupted.
- The oven may refuse to start, stop mid-cycle, or disable a specific feature linked to the fault.
- The fault may return straight after a reset if the underlying issue is still present.
- A fault that AEG lists as requiring a service call-out.
- Loose connection, sensor issue, or component fault in the affected circuit.
- Temporary software or control-board glitch if the code appeared once after a power interruption.
- Note exactly when the code appears: at startup, during preheat, when using a probe, or when trying a connected feature.
- Remove accessories that might be connected to the fault, such as a roasting thermometer or network setup step, and test again if that is safe.
- Record the model, code, and any recent power cuts or software updates before contacting support.
| Checkpoint | What to confirm | Good result | If it fails |
|---|---|---|---|
| Reset | Oven isolated for 60 seconds and restarted | Code clears | Move to targeted checks |
| Related feature | Affected part or feature checked safely | Oven works normally | Book service if fault returns |
| Repeat fault | Code stays away on retest | Likely temporary glitch | Persistent fault needs diagnosis |
- Assuming the code has cleared permanently after one reset without retesting the affected feature.
- Continuing to use the oven while the same code keeps coming back.
- Attempting internal electrical repairs without training.
- Do not dismantle oven panels or wiring unless you are qualified.
- Do not force sensors, probes, or connectors if they do not fit easily.
- Let the oven cool fully before checking lights, probes, or interior fittings.
- Isolate mains power before any inspection beyond simple user-accessible parts.
Contact AEG support or book service if F109 returns after the safe checks, or immediately if the affected component cannot be checked safely at home.
- Avoid pulling on cables, probes, or light fittings during cleaning.
- Keep connectors, lamps, and accessories fitted exactly as described in the user manual.
- Document unusual faults early instead of waiting for the oven to fail completely.
Can F109 be caused by a temporary glitch?
Sometimes yes, especially after a power interruption, but a repeat fault usually means the same underlying issue is still present.
Should I keep using the oven if it works after a reset?
Only if the code stays away and the related function works normally. If the same code returns, book support.