Hello, I'm trying to do the Clutch valve calibration in the basic settings of the transmission control unit on my 2015 Audi A7. Before I tried it wouldn't even start the procedure saying "(21) Function cannot be performed". All the criteria are met, transmission fluid was tried at 50 and 70°C, handbrake engaged, gear in Park, foot on brake. Then it worked suddenly on the other options in the menu such as main pressure valve calibration or the distance calibration, but when I tried the Clutch valve calibration, the process would start, the revs would increase but after a while it would show me "Exited due to reasons of safety". Does someone know why it's showing me this and why it sometimes starts and sometimes doesn't? Appreciate any advice, thank you.