Bosch Cooktop Error Code ER 35

ER 35 means the mTwist control system has detected a key selection error on the cooktop's control panel. The system identified an invalid or unresolvable input state from one or more keys. This causes the cooktop to disable itself to prevent unintended burner operation. The fault can originate from moisture, a stuck key, a damaged control panel, or a control board issue.

A power reset by turning off the circuit breaker for at least 5 minutes may clear ER 35 if the cause was a temporary condition such as a moisture-related false keypress. However, if an underlying hardware fault exists, such as a damaged control panel or failed board, the error will return after reset. A reset is a useful first diagnostic step but is not a repair.

Repair costs depend on the root cause. If only cleaning or a reset is needed, there may be no parts cost beyond a service call fee, which typically ranges from $75 to $150. Replacing a control panel assembly or main control board can bring total repair costs into the range of $200 to $500 or more, depending on the specific model and local labor rates.

Some causes of ER 35 are user-serviceable. Start by powering down the cooktop at the circuit breaker for several minutes, then inspect the control panel for moisture or debris before restoring power. If the error was triggered by a spill, thoroughly drying the panel surface may resolve it. If the error returns consistently, internal component replacement by a qualified technician is likely required.

You should not attempt to operate the cooktop while ER 35 is active. The error indicates the control system cannot reliably interpret user input, which means burner zones may not respond predictably. The cooktop disables itself as a safety measure, and bypassing or ignoring this condition is not recommended.