A computer aided instruction system which is composed of the followings, personal computers, microcomputer-controlled modules, and a vehicle simulation tester, has been installed in our college this April in oder to improve instructive officiency of the practice for automobile maintenance. This computer aided practice system for automobile maintenance, CAP, is peculiar with regard to the followings; (1) A mechatronic maintenance practice has been become feasible. (2) Each student can practice by himself on each personal computer's display connected with the vehicle simulation tester. (3) It has become possible to discipline each student in accordance with his comprehensive faculty by means of these CAI tools.