Method of checking vehicle mounted electronic units

摘要

An electronic unit mounted in a vehicle includes a controller unit. The electronic unit is tested by a test device using periodic communications cycled therebetween. A frame of order signal is formulated by loading data designating several ports or the like and transmitted from the test device to the controller unit. The controller unit processes the order signal and returns the processed results to the test device. At least part of the above data are shortened from 8 bits to 4 bits, and several ports and the like are tested in one cycle of the periodic communications. The testing time is thus reduced for the electronic unit.