Subaru 2002 Impreza Service Manual page 226

ELECTROHYDRAULIC CONTROL SYSTEM
I
Automatic Transmission
Signal name
Shift solenoid
1,
2
Line pressure duty solenoid
C: OUTPUT SIGNALS
Function
Each of these signals controls shift step by turning the corresponding solenoid ON/
OFF. Activating timing is controlled for each solenoid to reduce shift shock.
Regulates the line pressure according to driving conditions.
Torque control signal 1
Torque control signal 2
Lock-up duty solenoid
reverse inhibit function.
Reduces engine torque during range selection and gear change.
Reduces engine torque during range selection and gear change.
Regulates the hydraulic pressure of the lock-up clutch to operate it in three modes
(open, smooth and lock-up).
. .
. .
Regulates the hydraulic pressure of the transfer clutch to control the driving force to
the rear drive shaft.
Transfer duty solenoid
Causes the light to illuminate when ATF becomes excessively hot (exceeds a set tem-
perature level). This light is also used for on-board diagnostics.
AT OIL TEMP light
2-4 brake duty solenoid
I
Regulates 2-4 brake operating pressure to reduce shifting shocks.
2-4 brake timing solenoid
Switches on or off the pressure acting on 2-4 brake timing valve B to control the re-
lease timing of the 2-4 brake.
Low clutch timing solenoid
Switches on or off the pressure acting on the low clutch timing valve B to control the
release timing of the low clutch.
Also switches on or off the pressure acting on the reverse inhibit valve to control the
AT-4