Subaru 2002 IMPREZA Service Manual page 1680

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
O: DTC 77 LOCK-UP DUTY SOLENOID
DIAGNOSIS:
The output signal circuit of lock-up duty solenoid is open or shorted.
TROUBLE SYMPTOM:
No "lock-up" (after engine warm-up).
WIRING DIAGRAM:
B11
1 2 3 4 1 2
5 6 7 8
10 11 12
9 10 11 12
19 20 21
13 14 15 16
17 18 19 20
Step
1 CHECK DIAGNOSTIC TROUBLE CODE
(DTC).
B54
3 4
5 6 7 8 9
13 14 15 16 17 18
22 23 24
B54 TCM
B11
T4
AT3
TRANSMISSION
Check
Do multiple DTCs appear in
the on-board diagnostics test
mode?
AT-94
Yes
Go to another Go to step 2.
DTC.
TR0416
No