Oven does not heat and displays E03 shortly after start; fan may run but no elements energize.

Safety first: Isolate the oven from mains power before removing any covers. High voltages are present even when the oven is off.

• Check power supply: Verify the oven is receiving correct voltage at the wall outlet or junction box (typically 220–240 V AC for Blomberg ovens). If unsure, have a qualified electrician check.
• Inspect rear terminal block: Remove the rear cover to access the power terminal block. Look for burned terminals, loose screws, or melted insulation. Tighten connections and replace any damaged terminal block.
• Test heating elements: With power disconnected, disconnect one wire from each element (bake, grill, and, if present, fan element) and measure resistance. An open circuit (OL) indicates a failed element.
• Check thermal cut-outs: Locate the thermal cut-out or safety thermostat on the rear or top of the oven cavity. Test for continuity. If open and not resettable, it must be replaced.
• Control board check: If elements and TCOs test good, the heating relay on the main PCB may not be switching. Inspect for burn marks or cracked solder joints. Board replacement is usually required.