Subaru XT 1988 Service Manual page 569

AUTOMATIC TRANSMISSION AND DIFFERENTIAL
3-2
2) DUTY SOL. A (Line pressure) and DUTY SOL.B (Lock-up)
These solenoids are mounted to the control valve. They repeat
ON and OFF at 50 Hz (0.02 sec period)* according to signals
sent from the A/T control unit to open/close the drain circuit,
thereby controlling the oil pressure to a specified level.
*: A duty cycle type solenoid is used. It is capable of con-
trolling the ON/OFF time ratio in one cycle over the entire
range from 0 to 100%. For example, a duty ratio of 50
means 0.01 sec of ON period and 0.01 sec of OFF period
in one cycle of 0.02 sec.
Fig. 78
~ Duty ratio 50
ON
0.01
0.01
OFF~ ~
0.02
50 cycles per second
3) SOL. 3 (Overrunning clutch)
L3-655
This solenoid is also mounted to the control valve. It is turned
ON or OFF according to the signal sent from the A/T control
unit. This operation controls the engagement and disengage-
ment of the overrunning clutch.
4)
DUTY SOL. C (Transfer)
This solenoid is mounted to the transfer control valve on the
side face of the extension case. It repeats ON and OFF at
50 Hz (0.02 sec period) according to signals from the A/T
control unit. This operation opens and closes the drain circuit
to control transfer oil pressure.
\"Duty solenoid C (Transfer)
L3-656
Fig. 79
55
8) INHIBITOR SWITCH
The inhibitor switch assures safety when starting the engine.
This switch is mounted on the right side of the transmission
case, and is operated by the range selector lever.
When the selector lever is set to "P" or "N", the electrical
circuit is connected in the inhibitor switch and the starter
circuit is energized for cranking the engine.
When the selector lever is "R", "0", "3", "2", or "1st hold"
range, the electrical circuit is disconnected in the inhibitor
switch. Hence engine cranking is disabled. In the "R" range,
the backup light circuit is completed in the switch, and the
backup lights come on.
In addition to the above function, the inhibitor switch in-
corporates a circuit for detecting the selected range position
and sending the range signal to the A/T control unit.
L3-657
Fig. 80
~
NO.
1 2 3 4 5 6 7
8
9 10 12
'0
LgR
P~S:
Lg
GY
G 8
Y8
YW
8, GW
8Y
8W
G*
YLl\
GR
*
TION
P
0-
f.o
0-
t-o
R
N
0
-0
0-
t-o
0
..(')
3
0- e{)
2
*
1800 cc model
L3-968
Fig. 81