A method for state evaluation of a soot sensor in a motor vehicle

The invention relates to methods for onboard diagnosis of a soot sensor function and / or for the detection of other components in the soot in a motor vehicle with an internal combustion engine, the soot sensor is electrically connected to a permanently installed in the motor vehicle evaluation circuit. To provide a method for functional diagnosis of a soot sensor, and / or for the detection of other components in the carbon black, which would provide a cost-effective manner, an erroneous soot sensor and / or other components can be detected in the carbon black, the evaluation circuit measures the temperature coefficient of the soot sensor, and recognizes the defectiveness of the soot sensor and / or the presence of other components in the carbon black based on the temperature coefficient of the soot sensor.