Oven shows power supply or phase error; may not heat correctly on multi-phase installations.

Safety first: This involves live mains wiring. If you are not a qualified electrician, do not proceed; contact a professional.

• Verify wiring: With power off, remove the terminal cover and inspect the connection of L1, L2, L3 (if applicable), N, and PE according to the Miele wiring diagram. Correct any miswiring.
• Tighten terminals: Loose screws can cause arcing and phase loss. Tighten all terminal screws to the specified torque.
• Check supply: Using a multimeter, verify that all required phases and neutral are present at the wall connection. If a phase is missing, contact an electrician or utility provider.
• Internal fuses: Some models have internal line fuses on the control board. If accessible, test and replace blown fuses with identical types only.

Incorrect wiring can damage the oven and pose a fire risk; when in doubt, use a licensed electrician.