Patent ID: 8196460

Claim:
A method for monitoring an exhaust gas probe, which is disposed in an exhaust gas tract of an internal combustion engine, the method comprising the steps of: in relation to a jump of a variable influencing an air/fuel ratio from a leaner air/fuel ratio to a richer air/fuel ratio, capturing a measuring signal of the exhaust gas probe after a predetermined lean to rich delay period as a lean to rich signal value and relating the measuring signal of the exhaust gas probe to a lean reference signal value, which is captured in correlation with the jump of the variable influencing the air/fuel ratio from a leaner air/fuel ratio to a richer air/fuel ratio, in relation to a jump of the variable influencing an air/fuel ratio from a richer air/fuel ratio to a leaner air/fuel ratio, capturing a measuring signal of the exhaust gas probe after a predetermined rich to lean delay period as a rich to lean signal value and relating the measuring signal of the exhaust gas probe to a rich reference signal value, which is captured in correlation with the jump of the variable influencing the air/fuel ratio from a richer air/fuel ratio to a leaner air/fuel ratio, and identifying either an asymmetrically aged or a non-asymmetrically aged exhaust gas probe as a function of the related lean to rich and rich to lean signal values.