Subaru Legacy 2004 Service Manual page 2543

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
Step
7 CHECK AFTER REPAIR.
1) Perform the clear memory mode.
2) Drive for a while, read the DTC, and verify
that there is no faulty.
Check
Is DTC displayed?
5AT(diag)-84
Yes
Replace the TCM. Temporary poor
<Ref. to 5AT-61, contact or open
Transmission Con- circuit occurs.
trol Module Recheck that the
(TCM).> harness connec-
tor has no faulty.
No