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Electro-hydraulic Control System: General

The electro-hydraulic control system for the transmission and transfer consists of various sensors and switches, a transmission control module (TCM) and the control valves including solenoid valves. The system controls the automatic transmission operation, including gear shifting, lockup clutch operation, line pressure, pattern selection (NORMAL and SPORTS), and gear-shift timing. It also controls the operation of the transfer clutch. The TCM determines the vehicle's operating conditions from various input signals and controls a total of seven solenoids (line pressure linear solenoid, lockup duty solenoid, 2-4 brake duty solenoid, low clutch duty solenoid, high clutch duty solenoid, low & reverse duty solenoid, and transfer duty solenoid) by sending appropriate signals to them.

Fig 1: Flow Chart Of Electro-Hydraulic Control System
G03834421Courtesy of SUBARU OF AMERICA, INC.