check into vs check up on

check into

verb
  • To seek to verify (a claim or some data). 

  • To announce on social media that one has come to a location. 

  • To formally announce one's arrival at a location or event (usually a hotel) to a proprietor or employee of that location or event in order to secure admission, accommodations, or other services. 

check up on

verb
  • To examine or inspect something in order to determine its condition; to check out. 

  • To look after or inquire about someone's well-being. 

How often have the words check into and check up on occurred in a corpus of books? (source: Google Ngram Viewer )