From Longman Dictionary of Contemporary Englishcheck up on somebody/something phrasal verb1 CHECK/MAKE SUREto try to find out if someone is doing what they said they would do or what you want them to do Don’t worry; no one is going to check up on you.2 to make sure that something is true or correct Dustin called me to check up on some facts. → check→ See Verb table
Examples from the Corpus
check up on • If it's any consolation to you I needed to check up on a patient anyway.• I called Richard every day to check up on him.• Actually I sent my wife to check up on it.• It seems that every time I turn around, he is checking up on me.• It was my job to check up on the flock every morning and on Sundays Uncle Joe would come to the farm.• I made one loop and then another, returning to check up on the kids.• Catch the earliest flight down to London, check up on the Lennox twist.• The job, checking up on the moral character and life circumstances of sundry candidates for insurance, was in New York. 