Fault diagnosis method for an input shaft speed sensor of an automatic transmission
AssigneeHyundai Motor Company
InventorHyuk-Bin Kwon
Life of this patent
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Abstract
A fault diagnosis method is provided in which it is possible to determine whether the input shaft speed sensor of the automatic transmission is faulty by using the signals of the output shaft speed sensor, the brake switch, the engine speed sensor and so on, without making use of the signal of the vehicle speed sensor. Moreover, even if there are faults in the output shaft speed sensor or if the shift lever is positioned in the parking P range or the neutral N range, or if the engine speed is lower than the stall speed, the fault diagnosis method for the input shaft speed sensor can be performed, and additionally, a possibility of a misjudgment caused by a bad N-D hydraulic pressure response at an extremely low temperature can be removed.
Claims11
A fault diagnosis method for an input shaft speed sensor of an automatic transmission comprising:
- (a) determining whether a shift lever is positioned in a forward running range based on a signal of an inhibitor switch;
- (b) determining whether the input shaft speed sensor works properly by reading a first state flag if the shift lever is determined to be not positioned in a forward running range, and determining whether the shift lever is positioned in a parking P range or a neutral N range;
- (c) determining whether an automatic transmission fluid temperature is higher than a predetermined critical temperature if the shift lever is positioned in the parking P range or the neutral N range;
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- (d) separately determining whether the input shaft speed sensor is faulty according to whether a turbine speed is higher than a predetermined first critical speed, if the temperature of the automatic transmission fluid is higher than the predetermined critical temperature.
A fault diagnosis method for an input shaft speed sensor for an automatic transmission comprising:
- (a) determining whether a shift lever is positioned in a forward running range based on a signal of an inhibitor switch;
- (b) determining whether the input shaft speed sensor works properly by reading a first state flag if the shift lever is determined to be not positioned in a forward running range;
- (c) determining whether the shift lever is positioned in a parking P range or a neutral N range if it is determined that the input shaft speed sensor works properly;
- (d) determining whether an automatic transmission fluid temperature is higher than a predetermined critical temperature if the shift lever is determined to be positioned in the parking P range or the neutral N range;
- (e) determining whether the turbine speed is higher than a predetermined fifth critical speed if the input shaft speed sensor is determined to be faulty in step (b);
- (f) renewing the first state flag with a value indicating normal state of the input shaft speed sensor if the turbine speed is determined to be higher that the fifth critical speed in step (e);
- (g) determining whether an output shaft speed sensor works properly by reading a second-state flag if the shift lever is determined to be positioned in the forward running range in step (a);
- (h) determining whether an output shaft speed is higher than a predetermined fourth critical speed if the output shaft speed sensor works properly in step (g);
- (i) determining whether a brake switch works properly by reading a third-state flag if the transmission output shaft speed sensor is determined not to work properly in step (g), determining whether the brake switch is turned on if the brake switch works properly, and determining whether an engine speed is higher than a predetermined third critical speed if the brake switch is determined to be not turned on;
- (j) determining whether the engine speed is higher than a predetermined sixth critical speed if the brake switch is determined to not work properly, or if the brake switch is determined to be turned on;
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- (k) separately determining whether the input shaft speed sensor is faulty according to whether a turbine speed is higher than a predetermined first critical speed, if the temperature of the automatic transmission fluid is determined to be higher than the predetermined critical temperature in step (d), if the output shaft speed is determined to be higher than the predetermined fourth critical speed in step (h), if the engine speed is determined to be higher than the predetermined third critical speed in step (i), or if the engine speed is determined to be higher than the predetermined sixth critical speed in step (j).
Dependencies are inferred from the claim text.