Code P06A6-01

Question

I have a Ford Fiesta Ecoboost 100 2015 plate that has a issue when it rains, it loses power and puts the service now light on and goes in to limp mode, after a day and starting it up a few times it's ok, until it rains again.
I know it's a electrical problem but where would I start? Is this a common fault?

Thank you

Code p06A6-01