Ambient temperature/inlet air temperature sensor dither

Abstract

A computerized method diagnoses a vehicle temperature sensor. The method includes the steps of verifying a fault status for the sensor, and initializing a mileage based diagnostic when the default status indicates that no sensor faults are present. The mileage based diagnostic is conducted on the sensor upon initialization. The mileage based diagnostic is conducted by calculating a change in temperature and comparing the change in temperature to a predetermined temperature change. A change in mileage is also calculated and compared to a predetermined mileage change. The mileage based diagnostic further includes comparing a number of warmups for the vehicle to a predetermined number of warmups. The sensor is failed when the change in mileage reaches the predetermined mileage change, the number of warmups reaches the predetermined number of warmups, and the change in temperature does not reach the predetermined temperature change. Implementing a mileage based diagnostic allows stuck sensors to be detected with greater accuracy and improved customization on a vehicle-by-vehicle basis.

Dependencies are inferred from the claim text.