Smeg oven shows Er02 and does not start heating or stops mid-cycle.

Safety first: Isolate the oven from mains power. Allow the appliance to cool fully before working on it.

• Check ventilation: Ensure the oven is correctly installed with adequate ventilation gaps as per Smeg instructions. Remove any obstructions from front vents and cabinet cut-outs.
• Inspect cooling fan operation: Restore power briefly and start a cooking function. Listen for the top cooling fan (tangential fan) running. If it does not start within a few minutes, disconnect power again and inspect the fan behind the top panel for seized blades or burnt wiring. Replace the cooling fan motor if it does not spin freely or shows signs of overheating.
• Locate the safety thermostat: Remove the top or rear panel (depending on model). The safety thermostat (thermal cut-out) is usually mounted on the top of the oven cavity or rear panel with two wires attached.
• Reset or test the thermostat: Some Smeg safety thermostats have a small red reset button. Press it firmly to reset. If there is no reset button, test continuity with a multimeter. An open circuit when the oven is cold indicates a failed thermostat that must be replaced.
• Reassemble and test: After resetting or replacing the thermostat and confirming the cooling fan runs, reassemble panels, restore power, and test a low-temperature bake. If Er02 persists, the main control board may be misreading temperature and should be checked by a technician.