Why would you want to wipe it? the first thing a reliable repair shop will do - if it's possible - is wipe it, unless they have written instructions from you to not wipe it, and they agree.
If you're worried about some repairman getting your data, is it worth his job? (And hid freedom if it involves something like your passwords?) That's what any reliable shop will do. (I fired people for even looking in phones before repairing them. We usually wiped them in front of the customer, as er accepted the phone for repair.)