HOW DO YOU DETERMINE What causes check engine light on a 1995 v6 Toyota Camry?

sometihing is wrong in your engine and your computer is picking it up. It is a 95 model so you will have to go to a shop that has an OBD 1 computer and it will tell you what is wrong with your engine. Any vehicle under the year of 1996 takes the OBD 1 computer and 96 and up takes the OBD 2 computer.