reactivating start stop on 15 octavia

I am trying to reactivate the stop/start feature but am having issues. it was originally deactivated using carista but I have since got rid of that and got an obd11. I can access the gateway controller and I can and have reset the stop/start voltage parameters back to factory 7.4 v I think but this did not reactivate the system so I checked the temperature parameters and they are both set to 50c instead of the lower figure being set to -50c as per the factory. this is where I am having the issue it will not let me change this to -50 or any figure to be precise I just get a red banner with 31 function not available I have tried entering the security access code but this makes no difference. any ideas or would I be better off trying the soft reset option?