Patent ID: 8620516

Claim:
A vehicle system comprising: an internal combustion engine configured to selectively assume one of a plurality of operational states; a coolant system provided with the internal combustion engine and having a variable coolant flow; a temperature sensor provided with the internal combustion engine and configured to monitor a material temperature of a portion of the engine; and a computer implemented diagnostic module in communication with the internal combustion engine, with the temperature sensor, and with the coolant system, the diagnostic module configured to: receive an indication of the monitored material temperature; monitor the coolant flow of the coolant system; monitor the operational state of the internal combustion engine; and estimate an amount of accumulated energy within the internal combustion engine from the monitored coolant flow and operational state of the internal combustion engine; compare the estimated amount of accumulated energy to a first threshold; compare the indication of monitored material temperature to a second threshold; and determine that the temperature sensor is rational if the indication of monitored material temperature exceeds the second threshold before the estimated amount of accumulated energy exceeds the first threshold.