Can cold affect electronics? Yes. Most devices have operating guidelines for temperature ranges they can operate in. Most vehicles go through cold weather testing to see
how low the electrons can go. Doubt your tuner went through the rigorous testing your truck did. Probably the sub-zero temps in PA the last few weeks were below its operating range. If there is moisture that somehow got in there, may be able to dry it out with either the rice or silica gel methods. You may still be able to get it to work again.
Cold Weather Can Damage, Zap Electronic Devices