Method for diagnosing malfunction of pneumatic control device for internal combustion engine of motor vehicle, involves providing limits between which depressions are to be measured in pneumatic branch by predetermined functional gauge

摘要

The method involves measuring output signal of a pressure sensor (19), and measuring depression in a pneumatic branch (18) for a control instruction of a solenoid valve (4). A malfunction of a part of a pneumatic control device (1) is diagnosed on basis of comparison between the measured depression and a predetermined functional gauge. Limits between which the depressions are to be measured in the pneumatic branch according to instructions of the solenoid valve are provided by the predetermined functional gauge.