Method for determining a characteristic value of a magnetic switch valve , which can be switched from a first switch state (A) into a second switch state (B) by movement of a rotor by means of a switching magnet to which current is applied, against a conservative restoring force , wherein the first switch state is either a closed switch state or an open switch state and the second switch state is correspondingly either the open switch state or the closed switch state and wherein the the characteristic value belongs to a group, comprising: • the time required for switching the switch valve from the second switch state into the first switch state, • the spring constant of the restoring force , • the coefficient of friction effective during the valve actuation and • the switching path (AH), which the rotor covers when switching between the first (A) and the second (B) state, wherein during the switching of the switch valve from the second (B) into the first (A) state, the time course of the current (I) flowing through the switching magnet and/or of the voltage (U) at the switching magnet is measured, and the characteristic value is evaluated from this time course, characterized in that the time attenuation course is determined with which the potential energy stored in the magnetic circuit formed by the rotor and the switching magnet against the restoring force in the case of the position of the rotor fixed in the second and/or first state is dissipated in the ohmic resistor of the magnetic circuit, and in that the stored potential energy is evaluated as an integral over the attenuation course for the second state (B) between a first point in time, at which the rotor begins to move by means of the restoring force when switching from the second (B) into the first (A) state, and a second point in time, at which the rotor first strikes the end position thereof during said switching. • the time required for switching the switch valve from the second switch state into the first switch state, • the spring constant of the restoring force , • the coefficient of friction effective during the valve actuation and • the switching path (AH), which the rotor covers when switching between the first (A) and the second (B) state, wherein during the switching of the switch valve from the second (B) into the first (A) state, the time course of the current (I) flowing through the switching magnet and/or of the voltage (U) at the switching magnet is measured, and the characteristic value is evaluated from this time course, characterized in that the time attenuation course is determined with which the potential energy stored in the magnetic circuit formed by the rotor and the switching magnet against the restoring force in the case of the position of the rotor fixed in the second and/or first state is dissipated in the ohmic resistor of the magnetic circuit, and in that the stored potential energy is evaluated as an integral over the attenuation course for the second state (B) between a first point in time, at which the rotor begins to move by means of the restoring force when switching from the second (B) into the first (A) state, and a second point in time, at which the rotor first strikes the end position thereof during said switching. <EOS>