Method for condition determination of an exhaust-gas purification system

A process for calibrating a measurement device for measuring electrical properties of a component for exhaust-gas aftertreatment, which component stores exhaust-gas constituents and is arranged in an exhaust-gas aftertreatment system of a vehicle, comprising

• measuring, as a base measurement, the electrical properties of the component by the application of microwaves, the base measurement being made in a preliminary operation of the component, prior to any aging of the component, and while the component is at a temperature below a predetermined threshold temperature,
• measuring, as a normal operation measurement, the electrical properties of the component by the application of microwaves, the normal operation measurement being made during normal operation of the component, and while the component is at a temperature below the predetermined threshold temperature,
• determining a difference between the electrical properties measured in the normal operation measurement and the electrical properties measured in the base measurement, and designating the determined difference as a corrective value,
• measuring, as a normal driving measurement, the electrical properties of the component by the application of microwaves, the normal driving measurement being made during normal driving operation of the component, and while the component is at a temperature above the predetermined threshold temperature, and
• calibrating the measurement device by correcting the electrical properties measured in the normal driving measurement by application of the corrective value,
• wherein, the predetermined threshold temperature is a temperature at or below which measured electrical properties of the component in a laden state and measured electrical properties of the component in an unladen state differ by 10% or less.