Subaru 2002 Impreza Service Manual page 242

TRANSMISSION CONTROL MODULE (TCM)
Automatic Transmission
E: LINE-PRESSURE CONTROL
0
The oil pump delivery pressure (line pressure) is regulated to a constant pressure by the pilot
valve. This pressure is used as the pilot pressure for controlling spool valves.
0
The pilot pressure applied to the pressure modifier valve is modulated by the line pressure duty
solenoid into the pressure modifier pressure.
0
The pressure modifier valve is an auxiliary valve for the pressure regulator valve, and it creates
a signal pressure (pressure modifier pressure). The pressure modifier pressure is used to regulate
the line pressure to a level optimum for a particular driving condition.
0
This pressure modifier pressure is applied to the pressure regulator valve which controls the oil
pump delivery pressure.
0
The pressure modifier pressure from the pressure modifier valve is cushioned by the pressure
modifier accumulator to remove pulsation of the pressure.
(1 ) Relief valve
(2) Pilot valve
(3) Line pressure
(4)
Pilot pressure
( 5 ) Filter
(6) Line pressure duty solenoid
NFOO84
(7) Filter (1 3) Pressure regulator valve
(8) Accumulator (14) Oil pump
(9) Pressure modifier valve
(15) ON
(1 0)
To ATF cooler circuit (16) OFF
(11)
Accumulator
(12) From R range pressure circuit
AT-20