A method and device for monitoring a fuel metering system, in which fuel is pumped from a low-pressure zone into a high-pressure zone. The pressure in the high-pressure zone is detected. An error is recognized on the basis of the pressure variation in the high-pressure zone. The type of error is recognized on the basis of the shape of a pressure drop curve. The variation of the pressure quantity over time is approximated using a function such as the hyperbolic function. The type of error is recognized on the basis of the quantity characterizing the function.