Dryer will not start; display shows E01 shortly after pressing Start.

Safety first: Unplug the dryer or switch off the circuit breaker before any work. Do not bypass the door lock for testing while the machine is powered.

Step-by-step checks:

• Inspect the door latch: Open and close the door firmly. Check that the plastic/metal latch hook on the door engages fully with the catch in the cabinet. If the hook is loose, cracked or missing, the control will not detect a closed door.
• Check for door play: Gently lift the door up and down. Excessive play at the hinge can prevent the door switch from closing. Tighten hinge screws from the front panel if accessible.
• Test the door switch: With power disconnected, remove the front panel trim around the door (on many Neff dryers the door switch is mounted behind the front flange). Locate the door interlock assembly and disconnect its wiring plug. Using a multimeter, test continuity across the switch terminals while manually pressing the latch lever. It should show closed (0 Ω) when the door is latched and open (OL) when released.
• Inspect wiring: Follow the harness from the door lock to the main control module. Look for pinched, broken or burnt wires, especially near the hinge area where flexing occurs.
• Re-seat connectors: At the control board, unplug and re-plug the door lock connector to clear any poor contact.

If the switch has no continuity when actuated or shows intermittent readings, replace the complete door lock / door switch assembly with a compatible Neff part.