Princess oven displays E3 and the fan or heating does not start, or stops shortly after starting.

Safety first: Disconnect mains power before removing any covers. Fans can start unexpectedly when power is applied.

• Listen for fan operation: When the oven is first turned on (before disconnecting power), note whether you hear the cooling fan or convection fan start. No sound suggests a fan or power issue.
• Inspect fan blades: Remove the rear panel (for cooling fan) or inner rear cover (for convection fan) and check for grease buildup, foil, or debris jamming the blades. Clean and free the fan.
• Check wiring: Verify the fan motor connectors are tight and wires are not burned or broken.
• Test fan motor: With the oven unplugged, disconnect the fan motor and measure its resistance. An open circuit indicates a failed motor. If comfortable and safe, you can briefly power the fan motor with an appropriate test lead to confirm operation (only if you are trained to work with mains voltage).

If the fan motor is good but E3 persists, the fan control relay or triac on the main control board may be defective and the board will need replacement.