An electronic control apparatus of an air-bag system and a method of diagnosing the status of a back-up capacitor in an electronic control apparatus of an air-bag system

摘要

An electrical control apparatus for an air-bag system capable of inhibiting the diagnosis of back-up capacitors (151,152) when a diagnosing routine is initiated by an extraneous noise. In a main routine executed by a microcomputer (132) provided in an electrical control apparatus for an air-bag system, data stored in a specific address of a volatile memory (135) is read out, and it is determined whether or not its value is the same as a fixed value. If the result is affirmative, it is determined that the main routine is started by an extraneous noise, an ignition flag IG is reset, and the diagnosis of the back-up capacitors is inhibited. On the other hand, if the data does not have the same value as the fixed value, it is determined that the ignition switch is turned on again after it has been turned off, the IG is set, and the diagnosis for back-up capacitors is carried out.