Unit Repair Manual

DESCRIPTION
General Description





The A245E and A246E are 4-speed Electronically Controlled Transaxles. They feature a lock -up mechanism developed exclusively for use with transversely mounted engines. They have the following additional features.

- The "Super-Flow" torque converter improves transaxle efficiency.
- The transaxle control ECM has been integrated with the ECM.
- To reduce transaxle shift shock, ECM control at the shift point reduces engine torque and the clutch hydraulic pressure.

The automatic transaxle is mainly composed of a torque converter with lock-up clutch, 4 speed planetary gear unit, hydraulic control system and an electronic control system. To minimize the possibility of incorrect operation of the automatic transaxle, a shift lock mechanism has also been added.

General Specifications





OPERATION





1. Function Of Components








2. Hydraulic Control System




The hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, the accumulators, the clutches and brakes 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 3 solenoid valves on the valve body.

The No. 1 and No.2 solenoid valves are turned on and off by signals from the ECM to operate the shift vales 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.

3. Electronic Control System
The electronic control system for the A245E and A246E automatic transaxles provides extremely precise control of the gear shift timing and lock- up timing in response to driving conditions as low sensed by various sensors located throughout the vehicle and in response to the engine's running condition.

At the same time, the ECM control reduces vehicle squat when the vehicle starts out and gear shift shock.

The electronic control system is also equipped with a self diagnosis system which diagnoses malfunctions of electronically controlled components and warns the driver, and a fail-safe which makes it possible for the vehicle to continue functioning when a malfunction occurs.

Construction



The electronic control system can be broadly divided into 3 groups; the sensors, ECM and actuators.