Subaru Legacy 2002 Service Manual page 1859

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Automatic Transmission (Diagnostics)
N: DTC 77 LOCK-UP DUTY SOLENOID
DIAGNOSIS:
Output signal circuit of lock-up duty solenoid is open or shorted.
TROUBLE SYMPTOM:
No "lock-up" (after engine warm-up).
WIRING DIAGRAM:
No.
1 CHECK DTC.
Step
Do multiple trouble codes
appear in the on-board
diagnostics test mode?
AT-90
S004521I23
Check
Go to another
Diagnostic trouble
code (DTC).
TR0416
Yes No
Go to step 2.