Bosch induction cooktop shows E25 and zones shut off or cannot be activated.

Safety first: Turn off power at the breaker before accessing the underside of the cooktop.

• Check for obstruction: Remove the cooktop and visually inspect the cooling fan. Clear any insulation, wiring, or debris blocking the blades.
• Spin test: Gently spin the fan by hand. It should rotate freely without grinding. If stiff or noisy, replace the fan.
• Check wiring: Ensure the fan connector is fully seated on the control board and that wires are not pinched.
• Replace fan assembly: If the fan does not run when the cooktop is on and E25 appears, replace the cooling fan assembly. If a new fan does not resolve the error, the control module may not be reading the tach signal and will need replacement.