Patent ID: 8798892

Claim:
A method for the dynamic monitoring of a first lambda probe arranged in an exhaust-gas duct of an internal combustion engine upstream of an exhaust-gas purification system, a period of an output signal of the first lambda probe is determined in a controller of the internal combustion engine, and a lambda regulating signal is determined from an output signal of a second lambda probe connected downstream of the exhaust-gas purification system, characterized in that a first threshold value for a lengthening of the period of the output signal of the first lambda probe is predefined, in that a characteristic signal ( 46 ) is derived from the lambda regulating signal, in that a second threshold value for an inadmissible deviation of the characteristic signal ( 46 ) is predefined, and in that an inadmissible asymmetric delay of the first lambda probe is inferred if the lengthening of the period exceeds the first threshold value and the characteristic signal ( 46 ) deviates from the second threshold value outside predetermined limits.