We’d say no, and not just as a liability disclaimer. Thermador oven control boards sit close to line-voltage wiring, and the panel housing is designed to be serviced with the unit properly de-energized at the breaker — not just unplugged or switched off at a wall control. Beyond the shock risk, opening the housing without knowing exactly which part a given problem points to on your specific model risks disturbing wiring or connectors that had nothing to do with the original problem.
If you’re comfortable with one DIY step, it’s the safe one: pressing any key to clear the alert tone and reset the unit, then noting exactly what the display showed and when it recurred. Having that detail already written down saves the technician a round of trying to reproduce the problem.