Abstract: A transmission includes a gearing arrangement configured to shift speed ratios by disengaging an off-going shift element and engaging an oncoming shift element and an electrohydraulic valve having an actuatable valve element configured to control an engagement state of the oncoming shift element. A controller is programmed to, during a shift of the transmission, in response to the off-going shift element disengaging and an expected ratio change not initiating, monotonically increase current to the valve to a maximum value to overcome frictional resistance on the valve element, and programmed to, in response to expiration of a timer and the ratio change still not initiating, send a repeating pattern of high and low current signals according to a duty cycle to overcome frictional resistance of the valve element.

Abstract: A transmission includes a gearing arrangement configured to shift speed ratios by disengaging an off-going shift element and engaging an oncoming shift element and an electrohydraulic valve having an actuatable valve element configured to control an engagement state of the oncoming shift element. A controller is programmed to, during a shift of the transmission, in response to the off-going shift element disengaging and an expected ratio change not initiating, monotonically increase current to the valve to a maximum value to overcome frictional resistance on the valve element, and programmed to, in response to expiration of a timer and the ratio change still not initiating, send a repeating pattern of high and low current signals according to a duty cycle to overcome frictional resistance of the valve element.

Abstract: A vehicle includes an engine and a transmission having an input shaft operably coupled to the engine, an output shaft operably coupled to wheels of the vehicle, a primary pump, and a secondary pump. The primary and secondary pumps are each configured to supply pressurized fluid to a valve body of the transmission. A controller is programmed to, in response to a loss of pressure of the primary pump and a speed of the output shaft exceeding a first threshold, shift the transmission to a neutral state, energize the secondary pump once the transmission is in the neutral state, and command the engine to idle speed.

Abstract: A vehicle transmission includes a plurality of friction clutches and a selectable one-way clutch. The transmission also includes a controller programmed to, in response to detecting a component fault, switch the selectable one-way clutch from a passive state to an active state by commanding engagement of a first subset of the friction clutches to establish a slip elimination state. The controller is also programmed to, following establishment of the slip elimination state, command the selectable one-way clutch to the active state.

Abstract: A vehicle transmission includes a plurality of friction clutches and a selectable one-way clutch. The transmission also includes a controller programmed to, in response to detecting a component fault, switch the selectable one-way clutch from a passive state to an active state by commanding engagement of a first subset of the friction clutches to establish a slip elimination state. The controller is also programmed to, following establishment of the slip elimination state, command the selectable one-way clutch to the active state.

Abstract: A system and method for controlling a vehicle include a manual transmission operated by a controller in communication with shift actuators and programmed to, in response to each controller reset less than a threshold number of resets, control each shift actuator that was not moving at the time of the reset based on respective shift actuator positions stored prior to the reset, and to control the shift actuators to limit available gear ratios in response to the reset exceeding the threshold number of resets.

Abstract: A transmission diagnostic system includes a pivotable member and an actuator. The actuator has a notch with a first side, a second side, and an opening between the two sides. The width of the opening is greater than a width of the pivotable member. The pivotable member is retained within the notch, and the actuator is configured to selectively pivot the pivotable member between an engaged position, corresponding to a PARK gear, and a disengaged position, corresponding to a gear other than PARK. The transmission diagnostic system also includes a biasing spring configured to exert a biasing torque on the pivotable member to bias the pivotable member toward the first side of the notch. The transmission diagnostic system further includes a controller configured to generate at least one diagnostic signal in response to the pivotable member not being in contact with the first side of the notch.

Abstract: An exemplary pump condition response method includes, in response to a pump condition, operating an engine to discontinue or prevent a first stop-start cycle during a drive cycle. The method permitting a second stop-start cycle during the drive cycle.

Abstract: A system and method for controlling a vehicle include a manual transmission operated by a controller in communication with shift actuators and programmed to, in response to each controller reset less than a threshold number of resets, control each shift actuator that was not moving at the time of the reset based on respective shift actuator positions stored prior to the reset, and to control the shift actuators to limit available gear ratios in response to the reset exceeding the threshold number of resets.

Abstract: An exemplary pump condition response method includes, in response to a pump condition, operating an engine to discontinue or prevent a first stop-start cycle during a drive cycle. The method permitting a second stop-start cycle during the drive cycle.

Abstract: A vehicle according to the present disclosure includes a shift-by-wire transmission, a pressure source configured to selectively provide hydraulic pressure in the absence of engine power, an internal combustion engine, and a controller. The shift-by-wire transmission includes a hydraulic actuator, and the electric pump is in fluid communication with the actuator. The controller is configured to, in response to a driver input and the engine being off, control the pressure source to provide hydraulic pressure to the hydraulic actuator.

Abstract: A voting strategy is used to determine the mode state of a transmission when a vehicle is restarted. The transmission includes a return to park feature and a controller including at least three memories. The controller is configured to write a remembered mode state into each memory. The remembered mode state is one of a Normal mode state that allows the transmission to automatically shift to Park, a hold mode state that causes the transmission to remain in Neutral and not automatically shift to Park upon detecting a triggering event or other mode states. The controller reads each memory and, when at least two of the remembered mode states are the same mode state, causes the transmission to enter a mode state corresponding to the same mode state.

Abstract: A transmission diagnostic system includes a pivotable member and an actuator. The actuator has a notch with a first side, a second side, and an opening between the two sides. The width of the opening is greater than a width of the pivotable member. The pivotable member is retained within the notch, and the actuator is configured to selectively pivot the pivotable member between an engaged position, corresponding to a PARK gear, and a disengaged position, corresponding to a gear other than PARK. The transmission diagnostic system also includes a biasing spring configured to exert a biasing torque on the pivotable member to bias the pivotable member toward the first side of the notch. The transmission diagnostic system further includes a controller configured to generate at least one diagnostic signal in response to the pivotable member not being in contact with the first side of the notch.

Abstract: A vehicle includes both a transmission park mechanism and an electronic parking brake. As a failure management strategy, a controller monitors vehicle movement to verify that the park mechanism is successfully restraining the vehicle against movement. Specifically, when the driver releases the brake pedal with the transmission park mechanism commanded to restrain the vehicle, the controller waits for a predetermined amount of time. If the vehicle moves during this time, the controller commands application of the electronic parking brake. The controller may also command application of the electronic parking brake if the vehicle does not come to a stop after the transmission park mechanism is commanded to restrain the vehicle.

Abstract: A vehicle includes both a transmission park mechanism and an electronic parking brake. As a failure management strategy, a controller monitors vehicle movement to verify that the park mechanism is successfully restraining the vehicle against movement. Specifically, when the driver releases the brake pedal with the transmission park mechanism commanded to restrain the vehicle, the controller waits for a predetermined amount of time. If the vehicle moves during this time, the controller commands application of the electronic parking brake. The controller may also command application of the electronic parking brake if the vehicle does not come to a stop after the transmission park mechanism is commanded to restrain the vehicle.

Abstract: A vehicle according to the present disclosure includes a shift-by-wire transmission, a pressure source configured to selectively provide hydraulic pressure in the absence of engine power, an internal combustion engine, and a controller. The shift-by-wire transmission includes a hydraulic actuator, and the electric pump is in fluid communication with the actuator. The controller is configured to, in response to a driver input and the engine being off, control the pressure source to provide hydraulic pressure to the hydraulic actuator.

Abstract: A method and system provides a Neutral Hold mode in a vehicle having a shift-by-wire transmission with a return to park feature. The Neutral Hold mode is entered upon detecting when the transmission control mechanism has been used a first time to select Neutral when a driver's door is open or has been used a second time to select Neutral. When in Neutral Hold mode, the transmission will stay in Neutral and not shift to Park upon detecting that a driver has exited the vehicle.

Abstract: A method for an automatic transmission includes measuring torque of a component of the transmission using a torque sensor in communication with the component. The torque of the component is estimated from information other than the measured torque. The measured torque is rejected from being used in a control operation of the transmission if the difference between the measured torque and the estimated torque is greater than a selected threshold.

Abstract: A voting strategy is used to determine the mode state of a transmission when a vehicle is restarted. The transmission includes a return to park feature and a controller including at least three memories. The controller is configured to write a remembered mode state into each memory. The remembered mode state is one of a Normal mode state that allows the transmission to automatically shift to Park, a hold mode state that causes the transmission to remain in Neutral and not automatically shift to Park upon detecting a triggering event or other mode states. The controller reads each memory and, when at least two of the remembered mode states are the same mode state, causes the transmission to enter a mode state corresponding to the same mode state.

Abstract: A method and system provides a Neutral Tow mode in a vehicle with a shift-by-wire transmission by displaying a Neutral Tow mode option when the transmission control mechanism has been used to select Park, an ignition switch is on, and an engine is off or an information button has been pushed and entering a Neutral Tow mode upon detecting a triggering event. The Neutral Tow mode is canceled upon detecting a certain sequence of events, such as turning on the ignition switch, depressing and holding a brake pedal, and selecting Park. When in Neutral Tow mode the transmission will stay in Neutral, without automatically shifting to Park or using battery power, thereby enabling the vehicle to be towed long distances without draining battery power.