Basic Diagnostic Procedure - Subaru 2003 LEGACY Service Manual

AUTOMATIC TRANSMISSION (DIAGNOSTICS)

1. Basic Diagnostic Procedure

A: PROCEDURE
1 CHECK PRE-INSPECTION.
1) Ask the customer when and how the trou-
ble occurred using interview checklist.
<Ref. to AT-5, Check List for Interview.>
2) Before performing diagnosis, inspect the
following items which might influence the
AT problems.
•General inspection <Ref. to AT-6, INSPEC-
TION, General Description.>
•Oil leak
•Stall speed test <Ref. to AT-33, Stall Test.>
•Line pressure test <Ref. to AT-36, Line Pres-
sure Test.>
•Transfer clutch pressure test <Ref. to AT-38,
Transfer Clutch Pressure Test.>
•Time lag test <Ref. to AT-35, Time Lag Test.>
•Road test <Ref. to AT-32, Road Test.>
•Inhibitor switch <Ref. to AT-47, INSTALLA-
TION, Transmission Mounting System.>
Is unit that might influence the AT problem
normal?
2 CHECK POWER INDICATOR LIGHT.
Turn ignition switch to ON.
Does not the POWER indicator light light up?
3 CHECK POWER INDICATOR LIGHT.
1) Turn ignition switch to OFF.
2) Repair POWER indicator light circuit or
power supply and ground line circuit.
<Ref. to AT-30, Diagnostic Procedure for
POWER Indicator Light.>
3) Turn ignition switch to ON.
Is the POWER indicator light flashing?
4 CHECK INDICATION OF DTC.
Calling up the DTC.
Without Subaru Select Monitor
<Ref. to AT-24, WITHOUT SUBARU SELECT
MONITOR, OPERATION, Read Diagnostic
Trouble Code (DTC).>
With Subaru Select Monitor
<Ref. to AT-25, WITH SUBARU SELECT
MONITOR, OPERATION, Read Diagnostic
Trouble Code (DTC).>
NOTE:
If the communication function of the select
monitor cannot be executed normally, check
the communication circuit. <Ref. to AT-38,
COMMUNICATION FOR INITIALIZING IM-
POSSIBLE, Diagnostic Procedure for Select
Monitor Communication.>
Is the DTC displayed?
BASIC DIAGNOSTIC PROCEDURE
Step Value
Unit is normal.
Indicator light flashes.
Indicator light flashes.
DTC is displayed.
AT-2
Yes
Go to step 2. Repair or replace
each item.
Go to step 4. Go to step 3.
Go to step 4. Go to step 5.
Go to step 6. Go to step 5.
NOTE:
Record all DTCs.
No