Fuel tank firmness testing method for use in internal combustion engine of motor vehicle, involves testing opening characteristics of pressure switch for diagnosing operability of pressure switch after turning off of combustion engine

摘要

The method involves evaluating a switching status of a pressure switch (29), which communicates with an interior of a fuel tank (7). Opening characteristics of the pressure switch is tested for diagnosing operability of the pressure switch after turning off of an internal combustion engine (1). Complete data is transmitted to a motor control device (35) of the internal combustion engine during the diagnosis. The switching status is tested when a temperature difference exceeds a predetermined positive threshold value. An independent claim is also included for a device for testing firmness of a fuel tank of an internal combustion engine.