To check or investigate something in advance (so you won't have problems later).
明日の会議の資料は今夜のうちに調べて置くよ。
I'll look over the materials for tomorrow's meeting tonight.
駅の時刻表を調べておいてください。
Please check the train timetable beforehand.
ちょっと調べて置くね、すぐ戻るから。
I'll check it quickly and be right back.