Abstract: The present invention is a method for a microprocessor such that when a call is made to a subroutine or an interrupt, a return address is stored in a "stack" memory (RAM) and also that a particular piece of hardware write the return address to an additional register (latches) within the microprocessor. The method enables a comparison to be made at the end of the subroutine or interrupt such that the address to which the subroutine tries to return is compared to the address as latched into the hardware portion of the microprocessor to detect whether any human error has occurred in the programming of the interrupt program or the subroutine.

Abstract: The present invention is a method for invoking a shutdown on default and allowing recovery from a partial default. The method includes the steps of defining temporary default gears to be allowed for operation of the transmission, monitoring predetermined variables of the transmission by the controller and determining whether a fault has been detected based on the monitored predetermined variables. The method also includes disconnecting electrical power from the transmission by the controller if a fault has been detected, and determining whether faultless operation of the transmission has occurred for a predetermined time period by the controller if a fault has not been detected. The method further includes allowing shifting between additional gears if faultless operation of the transmission has occurred for the predetermined time period.

Abstract: The present invention is a method of fault protection for a microcomputer system. The method determines whether the system returns to a normal or special operating mode if a fault is detected by determining the microprocessor's past history before the fault occurred thereby allowing the microprocessor to get back on track in an appropriate manner.

Abstract: A method of engine determination is used in an electronically-controlled automatic transmission system. A transmission controller is capable of determining the particular engine model by data sent by the engine controller. The method includes determining whether the data received equals a first predetermined engine model byte stored in RAM. If not, the method determines whether the data received is valid. If so, the method determines whether the data received equals a second predetermined engine model byte stored in EEPROM.

Abstract: A method of monitoring an output and adjusting the action affecting the output continuously for an electronic automatic transmission system wherein a controller is programmed to "learn" from the results of its operation. The method includes monitoring the speed of an input member and the instantaneous fluid volume of a friction element. The method also includes setting a learned volume value equal to an instantaneous fluid volume whenever the input speed is within a predetermined range of a predetermined speed. The method further includes comparing the learned volume value to a stored fill volume value at the end of the shift and adjusting the stored fill volume value based on the difference between the learned volume value and the stored fill volume value.

Abstract: A method of determining the throttle angle position for an electronic automatic transmission system wherein a controller is programmed to determine the throttle angle position of the throttle in the engine and to detect any failures of the hardware used to determine throttle angle position and upon detecting a failure, providing a default throttle angle value to guarantee satisfactory operation.

Abstract: The present invention is a method of controlling the overall operation of an automatic transmission with an electronic controller. The method includes determining the gear the transmission should be operating in by the controller and comparing the determined gear to the gear the transmission is presently operating in by the controller to determine whether a gear change is required. The method further includes identifying and executing the proper gear change by the controller if a gear change is required.

Abstract: A method of sensing and determining open circuits and short circuits to the solenoid-actuated valves for the electronic automatic transmission.

Abstract: A method wherein a controller is programmed to determine the acceleration of the turbine in the torque converter to control transmission operation during a shift or gear change by counting the number of teeth during a predetermined cycle and dividing that tooth count by the actual time elapsed between the first and last tooth in an automatic transmission.

Abstract: The present invention is a method of organizing universally twelve different shifts into three sets of shifts for executing a set of shifts with the appropriate variable valves stored in memory for each shift.

Abstract: A method of shift selection in an electronic automatic transmission wherein a controller is capable of selecting between various desired transmission gear changes or shift patterns to place the transmission in the appropriate gear based on a plurality of input conditions. The method includes comparing a mask with a byte in a table row and determining whether a matching row was found. The method also includes pointing to the next row if a matching row was found and determining whether the present operating gear equals the next byte. The method further includes selecting the next byte to perform a predetermined gear change or selecting another byte to perform another predetermined gear change based on the present operating gear equaling the next byte, and executing the gear change selected.

Abstract: A method of determining the fluid temperature of an automatic transmission wherein a controller is programmed to determine the transmission temperature based on ambient and/or engine coolant temperatures and on observed transmission and engine warm-up rates. The controller may also be programmed to determine the transmission temperature based on the response of the pressure sensors provided.