Thermador Cooktop Error Code E0243

Error code E0243 on a Thermador induction cooktop indicates that the power board has detected a fault during its internal diagnostic check of the induction module's A/D (analog-to-digital) supply voltage converter. Specifically, the error is triggered when the power board cannot accurately measure the supply voltage on the left filter board side of the system. The A/D converter is responsible for translating analog voltage readings into digital signals the control board uses to monitor and regulate power delivery to the induction coils. When this measurement process fails, the board flags E0243 to prevent the cooktop from operating under unverified electrical conditions.

The left filter board is a critical component in the induction power circuit. It conditions incoming AC power before it reaches the inverter and coil assemblies. If the filter board itself has a fault, a failed capacitor, or a damaged trace, the supply voltage signal it presents to the A/D converter may be out of range or absent entirely. Similarly, a failure on the power board's own voltage sensing circuitry can produce this error even if the filter board is functioning correctly.

The first diagnostic step is to check the available supply voltage reaching the unit. A low, irregular, or absent supply voltage will prevent the A/D converter from taking a valid reading. This means verifying that the cooktop is receiving the correct line voltage at the terminal block or connection point before moving on to inspecting the filter board or the power board itself.