General System Description

PURPOSE
The A140E Electronically Controlled automatic transaxle is a lock-up four-speed automatic transaxle developed exclusively for use with transversely mounted engines.

OPERATION
The A140 E transaxle uses a combination of hydraulic and electronic control systems to control shift and lock-up characteristics.
HYDRAULIC CONTROL SYSTEM

The Hydraulic Control System:

The hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, the accumulator, the clutches and brakes, and the governor valve as well as the fluid passages which connect all of these components.
Based on the hydraulic pressure created by the oil pump, the hydraulic control system governs the hydraulic pressure acting on the torque converter clutch, clutches and brakes in accordance with the vehicle driving conditions.
There are three solenoid valves on the valve body.
The No.1 and No.2 solenoid valves are turned on and off by signals from the engine control module (ECM) to operate the shift valves and change the gear shift position.
The No.3 solenoid valve is operated by signals from the ECM to engage or disengage the lockup clutch of the torque converter clutch.
ELECTRONIC CONTROL SYSTEM

Automatic Transaxle Electronic Control System; Sensors And Actuators:

The electronic control system for controlling the shift timing and the operation of the lock-up clutch is composed of the following three parts:
(a) Sensors: These sense the vehicle speed and throttle position and send this data to the ECM in the form of electronic signals.
(b) Electronic Control Module: This determines the shift and lock-up timing based upon the signals from the sensors.
NOTE: This vehicle uses the Toyota Computer Controlled System (TCCS) which uses an integrated electronic engine and transmission control unit employing separate microprocessors for each function.
(c) Actuators: Solenoid valves divert hydraulic pressure from one circuit of the hydraulic control unit to another, thus controlling shifting and lock-up timing.