Miele · Professional Troubleshooting Guide
The oven has detected that the surrounding ambient temperature, likely around its control electronics, is too high, exceeding 85 degrees Celsius.
Click steps to track your progress.
Ensure there is adequate ventilation around the oven and that all cooling vents are not blocked.
Check for any external heat sources (e.g., another appliance) that might be raising the ambient temperature.
Turn off the oven's power supply at the circuit breaker and allow it to cool down.
Restore power and observe if the error clears once the ambient temperature is lower.