check into vs check up on

check into and check up on both are verbs.

Word	Noun	Adjective	Verb	Adverb
check into	No	No	Yes	No
check up on	No	No	Yes	No

As verbs, check into and check up on are synonyms defined as:

check into and check up on: examine so as to determine accuracy, quality, or condition

Other synonyms of check into include check, check out, check over, go over, look into, suss out.

check into (verb)	check up on (verb)
examine so as to determine accuracy, quality, or condition	examine so as to determine accuracy, quality, or condition