Oven shows E4 and the fan or grill functions may be disabled.

Safety first: Disconnect the oven from mains power and allow it to cool fully before accessing internal components.

Steps to diagnose and fix:

• Access the cooling fan: Remove the top cover or rear panel (depending on model) to reach the cooling fan assembly located above or behind the oven cavity.
• Check for obstructions: Try turning the fan blades by hand. They should spin freely. Remove any debris, insulation, or wiring that may be obstructing the blades.
• Inspect wiring: Follow the fan motor wires to the connector and main PCB. Look for burnt connectors, loose plugs, or damaged insulation. Reseat connectors firmly.
• Test the fan motor: With the motor disconnected and using a multimeter, check for continuity across the motor terminals. An open circuit indicates a failed motor that must be replaced.
• Replace the fan motor: If defective, remove the mounting screws, take out the old cooling fan motor, and install a new OBH Nordica-compatible cooling fan assembly. Ensure the fan rotates without rubbing against any surfaces.
• Control board check: If the motor tests good but does not receive power when the oven is hot, the fan relay or triac on the main control board may be faulty. In that case, the control board will need replacement.
• Test operation: Reassemble panels, restore power, and run the oven at a moderate temperature. Confirm that the cooling fan starts automatically and that E4 does not reappear.