Basic Diagnostic Procedure - Subaru Legacy 2003 Service Manual

ENGINE (DIAGNOSTICS)

1. Basic Diagnostic Procedure

A: PROCEDURE
1. ENGINE
1 CHECK ENGINE START FAILURE.
1) Ask the customer when and how the trou-
ble occurred using the interview check list.
<Ref. to EN(H4SO)-4, CHECK, Check List
for Interview.>
2) Start the engine.
Does the engine start?
2 CHECK ILLUMINATION OF CHECK ENGINE
MALFUNCTION INDICATOR LAMP (MI).
Does CHECK ENGINE malfunction indicator
lamp illuminate?
3 CHECK INDICATION OF DTC ON DISPLAY.
1) Turn ignition switch to OFF.
2) Connect the Subaru Select Monitor or the
OBD-II general scan tool to data link con-
nector.
3) Turn ignition switch to ON and the Subaru
Select Monitor or OBD-II general scan tool
switch to ON.
4) Read DTC on the Subaru Select Monitor or
OBD-II general scan tool.
Does the Subaru Select Monitor or OBD-II
general scan tool indicate DTC?
4 PERFORM THE DIAGNOSIS.
1) Inspect using "Diagnostics Procedure with
Diagnostic Trouble Code (DTC)".
NOTE:
<Ref. to EN(H4SO)-90, Diagnostic Procedure
with Diagnostic Trouble Code (DTC).>
NOTE:
Carry out the basic check, only when DTC
about automatic transmission is shown on dis-
play. <Ref. to EN(H4SO)-39, Read Diagnostic
Trouble Code.>
2) Repair the trouble cause.
3) Perform the clear memory mode. <Ref. to
EN(H4SO)-47, Clear Memory Mode.>
4) Perform the inspection mode. <Ref. to
EN(H4SO)-40, Inspection Mode.>
Does the Subaru Select Monitor or OBD-II
general scan tool indicate DTC?
BASIC DIAGNOSTIC PROCEDURE
Step Value
Engine starts.
MI illuminates.
DTC indicated.
DTC indicated.
EN(H4SO)-2
Yes
Go to step 2. Inspection using
"Diagnostics for
Engine Start Fail-
ure". <Ref. to
EN(H4SO)-62,
Diagnostics for
Engine Starting
Failure.>
Go to step 3. Inspection using
"General Diagnos-
tics Table". <Ref.
to EN(H4SO)-304,
INSPECTION,
General Diagnos-
tic Table.>
Go to step 4. Repair the related
parts.
NOTE:
If DTC
shown on display
although the MI il-
luminates,
form diagnostics of
MI (CHECK EN-
GINE malfunction
indicator lamp) cir-
cuit or combination
meter.
EN(H4SO)-50, En-
gine
Indicator
(MI).>
Inspect using Complete the
"Diagnostics Pro- diagnosis.
cedure with Diag-
nostic Trouble
Code (DTC)".
NOTE:
<Ref. to
EN(H4SO)-90, Di-
agnostic Proce-
dure with
Diagnostic Trou-
ble Code (DTC).>
No
is not
per-
<Ref. to
Malfunction
Lamp