Bosch Cooktop Error Code ER 25

ER 25 means the cooktop's control system has detected a false or incorrect mains supply connection. The unit monitors its incoming electrical supply and triggers this code when the wiring configuration does not match what the cooktop expects. This is a wiring-related fault, not a component failure, and it requires inspection of the power supply connections before the cooktop can operate safely.

No, you should not use the cooktop while ER 25 is active. The error indicates the power supply is connected incorrectly, which poses a risk of electrical damage to internal components and potentially a shock or fire hazard. The cooktop should remain powered off at the circuit breaker until the wiring has been inspected and corrected by a qualified technician.

If the problem is simply incorrect or loose wiring at the terminal block, repair costs typically reflect electrician or technician labor only, which can range from around 75 to 200 dollars depending on your location and the complexity of the installation. If the main control board has failed and requires replacement, total repair costs including parts and labor can range from roughly 200 to 500 dollars or more. Getting a diagnostic visit from a certified technician is the best way to determine the actual scope and cost.

Fixing ER 25 involves inspecting and correcting the high-voltage mains wiring at the terminal block and junction box, which carries serious shock risk. While a knowledgeable DIYer can visually inspect connections after confirming the breaker is off and voltage is absent at the terminals, any rewiring should be performed by a licensed electrician or appliance technician. Do not attempt to operate the cooktop while this error is active.

A power reset, such as switching the circuit breaker off and back on, will not permanently clear ER 25 if the underlying wiring problem has not been corrected. The control board checks the mains supply each time the unit powers on, so the error will return immediately if the incorrect wiring configuration remains. The fault must be resolved at the supply wiring level before the code will stay cleared.