System Outline

Previous automatic transmissions have selected each gear shift using mechanically controlled throttle hydraulic pressure, governor hydraulic pressure and lock­up hydraulic pressure. The electronically controlled transmission, however, electrically controls the line pressure, throttle pressure, lock­up pressure and accumulator pressure etc. through the solenoid valve. The electronically controlled transmission is a system which precisely controls gear shift timing and lock­up timing in response to the vehicle’s driving conditions and the engine condition detected by various sensors. It makes smooth driving possible by shift selection for each gear which is the most appropriate to the driving conditions at that time, and by preventing downing, squat and gear shift shock when starting off.

1.Lock­Up Operation

When the transmission control ECU decides based on each signal that the lock­up condition has been met, the current flows through TERMINAL SL of the transmission control ECU to TERMINAL 7 of the ECT solenoid to GROUND, causing lock­up operation.

2.Stop Lamp SW Circuit

If the brake pedal is depressed (Stop lamp SW on) when driving in lock­up condition, a signal is input to TERMINAL STP of the engine ECU. The engine ECU operates and cuts the current to the solenoid to release lock­up.