System Outline

Previous automatic transmissions have selected each gear shift using mechanically controlled throttle hydraulic pressure, governor hydraulic pressure and lock-up hydraulic pressure. The electronically controlled transmission, however, controls the line pressure, throttle pressure, lock-up pressure and accumulator pressure etc. electrically via the solenoid valve. The electronically controlled transmission is a system which precisely controls gear shift timing and lock-up timing in response to the vehicle driving conditions and the engine conditions detected by various sensors. It makes smooth driving possible by selecting the gear which is most appropriate to the driving conditions at that time.

1. Gear Shift Operation 

   When driving, the engine warm up condition is sent as a signal to TERMINAL THW of the engine control module from the engine coolant temp. sensor, and the vehicle speed signals from speed sensors are sent to TERMINAL SPD of the engine control module. via the combination meter. At the same time, the throttle valve opening signal is sent from the throttle body assembly to TERMINALS VTA1 and VTA2 of the engine control module as a throttle angle signal.

   Based on these signals, the engine control module selects the best shift position for the driving conditions and sends the appropriate current to the electronically controlled transmission solenoid.

2. Lock-Up Operation 

   When the received signals cause the engine control module the recognize that a LOCK-UP condition is needed, current flows from engine control module TERMINAL DSL to electronically controlled transmission solenoid TERMINAL 10. At the same time, current flows from engine control module TERMINAL SL1+ to the electronically controlled transmission solenoid TERMINAL 6 and from TERMINAL 13 to engine control module TERMINAL SL1-. This activates the LOCK-UP solenoid to perform a LOCK-UP operation.

3. Stop Light SW Circuit 

   If the brake pedal is depressed (Stop light SW on) while driving in a lock-up condition, a signal is sent to TERMINAL STP of the engine control module, the engine control module activates and cuts the current to the solenoid to release the lock-up.