Ambient temperature/inlet air temperature sensor dither
First Claim
1. A computerized method for diagnosing a vehicle temperature sensor, the method comprising the steps of:
- verifying a fault status for the sensor;
initializing a mileage based diagnostic when the fault status indicates that no sensor faults are present; and
conducting the mileage based diagnostic on the sensor upon initialization.
19 Assignments
0 Petitions
Accused Products
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.
34 Citations
20 Claims
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1. A computerized method for diagnosing a vehicle temperature sensor, the method comprising the steps of:
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verifying a fault status for the sensor;
initializing a mileage based diagnostic when the fault status indicates that no sensor faults are present; and
conducting the mileage based diagnostic on the sensor upon initialization. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
obtaining a reference temperature; and
obtaining a reference mileage.
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11. The method of claim 1 further including the steps of:
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calculating a change in temperature for the sensor;
comparing the change in temperature to a predetermined temperature change; and
passing the sensor when the change in temperature reaches the predetermined temperature change.
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12. The method of claim 11 further including the steps of:
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calculating a change in mileage for the vehicle; and
comparing the change in mileage to a predetermined mileage change.
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13. The method of claim 12 further including the steps of:
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comparing a number of warm-ups for the vehicle to a predetermined number of warm-ups; and
failing the sensor when the change in mileage reaches the predetermined mileage change, the number of warm-ups reaches the predetermined number of warm-ups, and the change in temperature does not reach the predetermined temperature change.
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14. The method of claim 13 wherein the predetermined temperature change, the predetermined mileage change, and the predetermined number of warm-ups are calibratable.
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15. A computerized method for conducting a mileage based diagnostic on a vehicle temperature sensor, the method comprising the steps of:
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calculating a change in temperature for the sensor;
comparing the change in temperature to a predetermined temperature change;
calculating a change in mileage for the vehicle;
comparing the change in mileage to a predetermined mileage change;
comparing a number of warm-ups for the vehicle to a predetermined number of warm-ups; and
failing the sensor when the change in mileage reaches the predetermined mileage change, the number of warm-ups reaches the predetermined number of warm-ups, and the change in temperature does not reach the predetermined temperature change. - View Dependent Claims (16, 17)
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18. A vehicle temperature sensor diagnostic system comprising:
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a fault status verification module for verifying a fault status for the sensor;
an initialization module for initializing a mileage based diagnostic when the fault status indicates that no sensor faults are present; and
a diagnostic module for conducting the mileage based diagnostic upon initialization. - View Dependent Claims (19, 20)
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Specification