E42 on an Electrolux dryer means the door is open or not fully closed, and EF1 means a ventilation blockage — the two most common, self-fixable codes. H4/B4 and H2/B2 point to wiring or power supply issues that typically need an installer or electrician rather than an appliance technician, since they relate to how the dryer is connected rather than a part inside it.
The documented code list
| Code | What Electrolux says it means |
|---|---|
| E42 | Door Open — check that the door is not blocked and is fully closed |
| EF1 | Ventilation Blockage |
| E4 | Humidity Sensor Failed |
| H4 / B4 | Incorrect wiring — a known installation issue |
| H2 / B2 | Power supply issue |
| AD | Auto Dry Setting |
| Mute | The unit has no sounds or alarm chimes (mute mode active) |
E42: Door open
Check that the door is closed fully and that nothing — a garment edge, a stray sock — is caught in the seal preventing it from latching. If the door appears closed but the code persists, the door switch itself may be misaligned or faulty.
EF1: Ventilation blockage
- Check the lint filter
Clean it fully even if it does not look heavily loaded — a partially blocked filter still restricts airflow enough to trigger this code.
- Check the exhaust tube
Look along its full length for bends, crushing, or restrictions, especially anywhere it was pushed against a wall.
- Check the vent exit outside
Confirm the exterior vent flap is not blocked by debris, lint buildup, or (seasonally) snow or leaves.
E4: Humidity sensor failed
Electrolux notes the dryer will still complete its current cycle and that manual (timed) cycles still operate normally even with this code present — it is the automatic moisture-sensing cycles specifically that are affected. If the code persists across multiple loads, this points to the sensor itself needing service rather than a one-off misread.
H4/B4 and H2/B2: Installation issues
These two codes are different from the others on this list — Electrolux documents them as installation-level problems rather than appliance faults. H4/B4 (incorrect wiring) and H2/B2 (power supply issue) both point to the electrical connection feeding the dryer rather than a component inside it, and Electrolux’s own guidance is to contact the installer or electric company respectively rather than an appliance repair technician.
Mute mode and AD
If the dryer has stopped making its normal end-of-cycle or alert sounds, check whether mute mode has been activated (often via a held button combination or a menu setting) rather than assuming a fault. AD refers to the Auto Dry setting, a normal cycle option rather than an error.
When to call a technician
A recurring E4 across multiple manual and automatic cycles, or an E42 that persists with the door confirmed fully closed, are the two codes on this list most likely to need parts replacement rather than a simple check. H4/B4 and H2/B2 need an installer or electrician, not an appliance repair call.
Stop and call a qualified appliance technician or electrician if you find scorched or melted wiring, smell burning, see water that has reached electrical components, or if the fault returns immediately after a repair. Never bypass a safety device — thermal fuses, door interlocks and flood switches fail for a reason, and defeating one converts a broken appliance into a fire or flood risk.
