Patent ID: 7588368

Claim:
A method for diagnosing operation of three temperature sensors each disposed at a different location along a single exhaust flow path fluidly connected to an exhaust manifold of an internal combustion engine, the method comprising: receiving a first temperature signal from a first of the three temperature sensors, receiving a second temperature signal from a second of the three temperature sensors, receiving a third temperature signal from a third of the three temperature sensors, determining an exhaust gas flow rate corresponding to a flow rate of exhaust gas flowing through the single exhaust flow path, determining a first average temperature differential between the first and second temperature sensors as a function of the first temperature signal, the second temperature signal and the exhaust gas flow rate, determining a second average temperature differential between the first and third temperature sensors as a function of the first temperature signal, the third temperature signal and the exhaust gas flow rate, and producing a first fault signal if a difference between the first and second average temperature differentials exceed a threshold value.