Bosch Cooktop Error Code ER 23

ER 23 on a Bosch cooktop indicates that the PWM (pulse-width modulation) frequency used to control the induction heating elements has moved outside of its acceptable operating range. PWM is the method by which the cooktop's control board rapidly switches power to the induction coils on and off to regulate heat output. The frequency at which this switching occurs must stay within a defined window for the system to operate safely and efficiently. When the control board detects that this frequency has drifted too high or too low, it triggers ER 23 and shuts down the affected zone to prevent damage.

The most likely source of this fault is the main power control board or the inverter circuitry responsible for generating and regulating the PWM signal. A failing power module, degraded capacitors, or damaged gate driver components can all cause frequency instability. Overheating of the electronics is another contributing factor, as thermal stress degrades the components that maintain precise PWM timing. In some cases, an incompatible or damaged induction coil assembly can create load conditions that push the inverter's output frequency outside its specified limits.

Because this error involves the core power switching electronics, it is not a fault that resolves through simple cleaning or resetting in most cases. A technician will typically inspect the inverter board and power module for visible damage such as burned components, swollen capacitors, or failed transistors. Replacement of the control or power board is the most common repair path when this code appears and persists after the unit has fully cooled.