Patent ID: 7137294

Claim:
A method for identifying defects in a fuel injection system wherein the fuel injection system includes a high-pressure pump, a fuel accumulator, a fuel pressure control valve, and a pressure sensor for recording the pressure prevailing in at least one fuel accumulator, comprising: identifying the occurrence of at least one defect in the fuel injection system by recording a pressure in the fuel accumulator that is too low and using a high-frequency component of a first signal characterizing the pressure course in the fuel accumulator over a time in order to isolate the source of the defect; comparing the pressure determined in at least one fuel accumulator with a desired pressure in a low-pressure area of the fuel injection system or a pressure that is actually present in the low-pressure area of the fuel injection system; and concluding that there is a defect in the low-pressure area if the pressure determined in the fuel accumulator is lower than the desired pressure, or concluding that there is a defect in the drive of the high-pressure pump if the pressure determined in the fuel accumulator is lower than the pressure that is actually present in the low-pressure area.