Subaru Legacy 2004 Service Manual page 2593

Diagnostic Procedure with Diagnostic Trouble Code (DTC)
AUTOMATIC TRANSMISSION (DIAGNOSTICS)
AR:DTC P1799 INTERLOCK
DTC DETECTING CONDITION:
Perform the interlock judgment when the oil pressure switch pattern detect the specified interlock patterns for
more than 2 seconds other than shifting.
TROUBLE SYMPTOM:
Locked to 2nd, 4th or 5th gear.
Step
1 CHECK DTC OF TCM.
2 CHECK DTC OF TCM.
3 CHECK POOR CONTACT.
Check
Is DTC of oil pressure switch
detected?
Is the DTC related to solenoid
function or solenoid circuit
detected?
Is there any open or poor con-
tact of connector (loosing ter-
minal, entering foreign matter,
damaging connector body)?
5AT(diag)-134
Yes
Perform the diag- Go to step 2.
nosis according to
DTC.
Perform the diag- Go to step 3.
nosis according to
DTC.
Repair the poor Replace the TCM.
contact. <Ref. to 5AT-61,
Transmission Con-
trol Module
(TCM).>
No