Bosch Range Error Code ER23

ER23 on a Bosch range indicates that the electric cooktop's MTwisT control module has detected a PWM (pulse width modulation) frequency that falls outside of its accepted operating limits. The MTwisT system is Bosch's knob-based induction or electric cooktop control interface that translates rotary user input into precise power level signals. PWM frequency is the method by which the control board regulates power delivery to the cooking elements by rapidly switching the circuit on and off at a specific frequency. When this frequency drifts too high or too low relative to the expected range, the control system flags it as ER23 and typically halts normal operation to prevent component damage.

The MTwisT control module communicates with the main cooktop control board via signal lines that carry these PWM signals. A fault in this communication path, whether caused by a failing MTwisT module, a damaged connection harness, or a compromised main control board, can result in the measured PWM frequency reading outside of specification. The error does not necessarily mean the cooking element itself has failed, but rather that the control signal governing it is corrupted or absent.

Common triggers include internal failure of the MTwisT rotary control unit, wiring harness issues between the MTwisT module and the main control board, or a fault within the main control board's PWM generation circuitry. Because this error is specific to the control signal pathway rather than the heating element or temperature sensor, diagnosis should focus on the MTwisT module, its connecting wiring, and the main control board.