Washer-dryer combo will not start; display shows D01 and cycle will not begin even though the door is closed.

Safety first: Unplug the Brandt washer-dryer combo from the mains before removing any panels. Do not bypass the door lock for operation; this is a critical safety device.

• Check door closure: Open and firmly close the door. Ensure no laundry is trapped between the door seal and the door glass. Try starting a cycle again.
• Inspect door latch hook: Examine the metal or plastic latch on the door. If it is loose, bent, or broken, the lock cannot engage. Replace the door latch hook if damaged.
• Test door lock assembly: Remove the front door seal clamp and gently pull back the seal to access the door lock. Check the connector for loose or burnt pins. Reseat the connector and test again. If the error persists, use a multimeter to check continuity of the lock’s main contacts; replace the door lock assembly if open.
• Check wiring harness: Trace the harness from the door lock to the main control board. Look for pinched, cut, or burnt wires. Repair or replace damaged wiring.
• Control board check: If the door lock and wiring are good but D01 remains, the main control board door-lock relay may be faulty. At this stage, replacement of the control board is recommended and is best done by a qualified technician.