Miele Softtronic T8423C service mode tumble dryer T8000 series

Instructions below:
Press and maintain pressed start/stop and on/off buttons
When quick blinking is done: unpress on/off (optional) and push 3 times start/stop and maintain pressed
When slow blinking: press 1 time start/stop
You can switch between infos with the wheel
Infos explanation:
then digits: software ID
F then digits: error codes
U then digits: component test (press start/stop to switch between them)
= then digits: switch/sensor test (door closed switch, etc.) (press start/stop to switch between them)
H then digits: operating hours counter display
Français :
Appuyer et maintenir start/stop et marche/arrêt
Lorsque fini de clignoter rapidement : lâcher marche/arrêt et appuyer 3x sur start/stop puis maintenir
Lorsque clignote lentement : appuyer 1x sur start/stop

[@domblondje99]

great this. Is there also an option to reset old error codes?

[@CARDGAMBIT]

When I switch on my T8422C it is non responsive, no lights come on at all. How can I figure out what’s wrong with it?