Subaru 2002 Impreza Service Manual page 240

TRANSMISSION CONTROL MODULE (TCM)
I
Automatic Transmission
Solenoid 1
1 st ON
2nd OFF
C: SHIFT CONTROL
The TCM performs gear shifting control according to driving conditions by using the shift point
characteristic data stored in its memory. Appropriate solenoids are operated at the proper timing
corresponding to the shift pattern, throttle position, and vehicle speed for smooth shifting.
NOTE:
When the ATF temperature is below approximately 10°C (50"F), the gear cannot be shifted to the
4th speed.
Solenoid 2
ON
ON
Large
3rd
4th
Small
~.
-
.
OFF OFF
ON OFF
Low High
Vehicle speed
TCM
c
I
I
I
I
I
NF0082
0
The TCM activates both solenoids 1 and 2 in response to throttle and vehicle speed signals.
0
Shift valves move in response to operation of the solenoids, supplying or interrupting the line
pressure to each clutch.
0
A shift to each gear takes place according to ON-OFF operation of both the solenoids as indi-
cated in the table above.
I
Shift clutches
I
Clutch fluid
r
I
I
L
Solenoi
i
Throttle position
I
Vehicle speed
I
I
NF0083
AT-I 8