Patent ID: 8286462

Claim:
A method for diagnosing the reliability performance of a first lambda probe which is located in the exhaust gas line in the outflow direction of an exhaust gas emerging from an internal combustion engine downstream from at least one section of a catalytic converter with an oxygen storage capacity, in which in a changing sequence lean exhaust gas and rich exhaust gas are supplied to the exhaust gas line in order to cause in alternation the absorption of oxygen by the catalytic converter and the re-release of the absorbed oxygen by the catalytic converter, wherein for diagnosis purposes at least one signal is used which has been received from the first lambda probe in the change from one of lean to rich and rich to lean exhaust gas, wherein using a second lambda probe located in the exhaust gas line upstream from the first lambda probe an instant of change is determined and that depending on this instant a time interval is defined and the signals picked up in the time interval by the first lambda probe are used for diagnosis, and wherein the time interval begins around the estimated and averaged transit time after the instant of change, which time the exhaust gas requires to transit the exhaust gas line from the second jump probe to the first jump probe.