No od IN 06 COBALT

Only problem is , ihave no od in the 06 cobalt ls 4t45-e that stopped working and it pulled ap0742 code , part # tsc39 , how ever i was told that now that it's pulled apart i should replace all 3 , which other's are there that i should do ? Because they were right i don't want to do this again any time soon ! This is my wife's car and she's off the deep end seeing all these part's and her car apart like it is. And ya know if moma's not happy , well, we all know that story so please help.