Subaru LEGACY 2002 Quick Reference Index page 283

2. Electrohydraulic Control System
A: GENERAL
1. MPT MODELS
The electrohydraulic control system for the transmission and transfer consists of various sensors
and switches, a transmission control module (TCM) and the hydraulic controlling units including
solenoid valves. The system controls the automatic transmission operation, including gear shift-
ing, lock-up clutch operation, line pressure, automatic control pattern selection ("Base" and "Pow-
er"), and gear-shift timing. It also controls the operation of the transfer clutch. The TCM determines
vehicle operating conditions from various input signals and controls a total of eight solenoids (shift
solenoids 1 and 2, low clutch timing solenoid, 2-4 brake timing solenoid, line pressure duty sole-
noid, lock-up duty solenoid, transfer duty solenoid, and 2-4 brake duty solenoid) by sending ap-
propriate signals to them.
INPUT
Throttle position sensor
Rear vehicle speed sensor
Front vehicle speed sensor
ECM
Engine speed signal
ATF temperature sensor
Inhibitor switch
HOLD switch
ECM
Intake manifold pressure signal
FWD switch
Battery voltage
ABS signal
Brake switch
Torque converter turbine speed sensor
ECM
Torque control cut signal
Cruise control signal
POWER switch
Kickdown switch
ELECTROHYDRAULIC CONTROL SYSTEM
TCM
Shift solenoid 1
Shift solenoid 2
Line pressure duty solenoid
Lock-up duty solenoid
Transfer duty solenoid
2-4 brake duty solenoid
2-4 brake timing solenoid
Low clutch timing solenoid
Torque control signal 1
Torque control signal 2
AT diagnosis signal (with OBD)
FWD indicator light
AT OIL TEMP light
POWER indicator light
HOLD indicator light
Speedometer circuit
AT-7
Automatic Transmission
OUTPUT
ON-OFF
ON-OFF
ECM
ECM
ECM
Combination meter
B3H2271A