Door will not lock and cycle will not start, E40 displayed.

Safety: Disconnect power before removing any panels.

• Check door closure: Ensure no clothing is trapped between door and seal. Firmly close the door until a click is heard.
• Inspect latch and catch: Examine the plastic door catch on the door and the lock opening on the cabinet for damage or misalignment. Tighten hinge screws if the door sags.
• Test door lock: Remove the front retaining band of the door seal and pull back the seal to access the AEG door lock. Check the connector is fully seated and wiring is intact.
• Replace lock if faulty: If the lock shows burn marks or fails continuity tests across the lock terminals, replace the door lock assembly.

If E40 persists with a new lock, the control board output to the lock may be defective and requires professional diagnosis.