Machine shows E13 and may not complete self-test; sometimes the brew unit cannot be inserted or removed.

Safety first: Turn off and unplug the machine before attempting to remove the brew unit.

Step-by-step:

• 1. Remove brew unit carefully: Follow the user manual's instructions for emergency removal if the unit is stuck. Do not force it, as this can break the locking mechanism.
• 2. Clean and inspect: Rinse the brew unit and inspect the locking lugs and guides for damage. Clean coffee residues from the brew chamber and locking area.
• 3. Check lock lever: Ensure the internal lock lever moves freely and is not obstructed by coffee grounds or broken plastic.
• 4. Reset machine: With the brew unit removed, plug in and power on the machine to allow the drive to return to its home position. Then power off, unplug, and reinstall the brew unit.
• 5. Professional repair: If E13 persists, the lock switch or mechanical lock assembly may need replacement by a Siemens technician.