Subaru Legacy III (2000-2003 year). Manual - part 203

EN(H4SOw/oOBD)-2

ENGINE (DIAGNOSTICS)

BASIC DIAGNOSTIC PROCEDURE

1. Basic Diagnostic Procedure

A: PROCEDURE

1. WITH SUBARU SELECT MONITOR

Step

Value

Yes

No

1

CHECK ENGINE START FAILURE.
1) Ask the customer when and how the trou-

ble occurred using the interview check list. 
<Ref. to EN(H4SOw/oOBD)-4, CHECK, 
Check List for Interview.>

2) Start the engine.

Does the engine start?

Engine starts.

Go to step 2.

Inspection using 
“Diagnostics for 
Engine Starting 
Failure”. <Ref. to 
EN(H4SOw/
oOBD)-39, Diag-
nostics for Engine 
Starting Failure.>

2

CHECK ILLUMINATION OF CHECK ENGINE 
MALFUNCTION INDICATOR LAMP (MIL).
<Ref. to EN(H4SOw/oOBD)-30, ACTIVATION 
OF CHECK ENGINE MALFUNCTION INDICA-
TOR LAMP (MIL), Engine Malfunction Indica-
tor Lamp (MIL).>
Does MIL illuminate?

MIL illuminates.

Go to step 3.

Inspection using 
“General Diagnos-
tic Table”. <Ref. to 
EN(H4SOw/
oOBD)-102, 
INSPECTION, 
General Diagnos-
tic Table.>

3

CHECK INDICATION OF DTC ON DISPLAY.
1) Turn ignition switch to OFF.
2) Connect the Subaru Select Monitor to data 

link connector.

3) Turn ignition switch to ON and the Subaru 

Select Monitor switch to ON.

4) Read DTC on the Subaru Select Monitor.

<Ref. to EN(H4SOw/oOBD)-24, WITH 
SUBARU SELECT MONITOR, OPERA-
TION, Read Diagnostic Trouble Code 
(DTC).>
Does the Subaru Select Monitor indicate 
DTC? <Ref. to EN(H4SOw/oOBD)-57, 
LIST, List of Diagnostic Trouble Code 
(DTC).>

DTC is displayed on Subaru 
select monitor.

Record diagnostic 
trouble code. 
Repair the trouble 
cause. <Ref. to 
EN(H4SOw/
oOBD)-59, Diag-
nostic Procedure 
with Diagnostic 
Trouble Code 
(DTC).>  Go to 
step 4.

Repair the related 
parts.

NOTE:
If DTC is not
shown on display
although the MIL il-
luminates, per-
form diagnostics of
MIL (CHECK EN-
GINE malfunction
indicator lamp) cir-
cuit or combination
meter. <Ref. to
EN(H4SOw/
oOBD)-30, Engine
Malfunction Indica-
tor Lamp (MIL).>

4

PERFORM THE DIAGNOSIS.
1) Perform the clear memory mode. <Ref. to 

EN(H4SOw/oOBD)-28, OPERATION, 
Clear Memory Mode.>

2) Perform the inspection mode. <Ref. to 

EN(H4SOw/oOBD)-26, OPERATION, 
Inspection Mode.>
Does the Subaru Select Monitor indicate 
DTC? <Ref. to EN(H4SOw/oOBD)-57, 
LIST, List of Diagnostic Trouble Code 
(DTC).>

DTC is displayed on Subaru 
select monitor.

Record diagnostic 
trouble code. 
Repair the trouble 
cause. <Ref. to 
EN(H4SOw/
oOBD)-59, Diag-
nostic Procedure 
with Diagnostic 
Trouble Code 
(DTC).>  Go to 
step 4.

Complete the 
diagnosis.

EN(H4SOw/oOBD)-3

ENGINE (DIAGNOSTICS)

BASIC DIAGNOSTIC PROCEDURE

2. WITHOUT SUBARU SELECT MONITOR

CAUTION:
• Check the connector while it is connected un-
less specified otherwise.

• Be sure to check again from the beginning in
order to prevent secondary trouble caused by
repair work.

Step

Value

Yes

No

1

CHECK ENGINE START FAILURE.
1) Ask the customer when and how the trou-

ble occurred using the interview check list. 
<Ref. to EN(H4SOw/oOBD)-4, CHECK, 
Check List for Interview.>

2) Start the engine.

Does the engine start?

Engine starts.

Go to step 2.

Inspection using 
“Diagnostics for 
Engine Starting 
Failure”. <Ref. to 
EN(H4SOw/
oOBD)-39, Diag-
nostics for Engine 
Starting Failure.>

2

CHECK ILLUMINATION OF CHECK ENGINE 
MALFUNCTION INDICATOR LAMP (MIL).
<Ref. to EN(H4SOw/oOBD)-30, ACTIVATION 
OF CHECK ENGINE MALFUNCTION INDICA-
TOR LAMP (MIL), Engine Malfunction Indica-
tor Lamp (MIL).>
Does MIL illuminate?

MIL illuminates.

Go to step 3.

Inspection using 
“9. General Diag-
nostic Table”. 
<Ref. to 
EN(H4SOw/
oOBD)-102, 
INSPECTION, 
General Diagnos-
tic Table.>

3

CHECK INDICATION OF DTC ON MIL.
1) Perform the read diagnostic trouble code 

(read memory mode).<Ref. to EN(H4SOw/
oOBD)-24, WITHOUT SUBARU SELECT 
MONITOR, OPERATION, Read Diagnos-
tic Trouble Code (DTC).>

2) Read DTC on MIL.

Does the MIL indicate DTC? <Ref. to 
EN(H4SOw/oOBD)-57, LIST, List of Diag-
nostic Trouble Code (DTC).>

DTC is displayed on MIL.

Repair the trouble 
cause. Go to step 
4.

Repair the related 
parts.

NOTE:
If DTC is not
shown on MIL al-
though the MIL illu-
minates, perform
diagnostics of MIL
(CHECK ENGINE
malfunction indica-
tor lamp) circuit or
combination
meter.<Ref. to
EN(H4SOw/
oOBD)-30, Engine
Malfunction Indica-
tor Lamp (MIL).>

4

PERFORM THE DIAGNOSIS.
1) Perform the clear memory mode. <Ref. to 

EN(H4SOw/oOBD)-28, OPERATION, 
Clear Memory Mode.>

2) Perform the inspection mode. <Ref. to 

EN(H4SOw/oOBD)-26, OPERATION, 
Inspection Mode.>
Does the MIL indicate DTC? <Ref. to 
EN(H4SOw/oOBD)-67, DTC 21 ENGINE 
COOLANT TEMPERATURE SENSOR, 
Diagnostic Procedure with Diagnostic Trou-
ble Code (DTC).>

DTC is displayed on MIL.

Repair the trouble 
cause. Go to step 
4.

Complete the 
diagnosis.

EN(H4SOw/oOBD)-4

ENGINE (DIAGNOSTICS)

CHECK LIST FOR INTERVIEW

2. Check List for Interview

A: CHECK

1. CHECK LIST NO. 1

Check the following items when problem has occurred.

NOTE:
Use copies of this page for interviewing customers.

Customer's name

Engine no.

Date of sale

Fuel brand

Date of repair

Odometer reading

km

Vin no.

miles

Weather

❏

 Fine

❏

 Cloudy

❏

 Rainy

❏

 Snowy

❏

 Various/Others:

Outdoor temperature

°

F (

°

C)

❏

 Hot 

❏

 Warm 

❏

 Cool 

❏

 Cold

Place

❏

 Highway 

❏

 Suburbs 

❏

 Inner city 

❏

 Uphill 

❏

 Downhill 

❏

 Rough road 

❏

 Others: 

Engine temperature

❏

 Cold 

❏

 Warming-up 

❏

 After warming-up 

❏

 Any temperature 

❏

 Others: 

Engine speed

rpm

Vehicle speed

MPH

Driving conditions 

❏

 Not affected 

❏

 At starting 

❏

 While idling 

❏

 At racing 

❏

 While accelerating 

❏

 While cruising 

❏

 While decelerating 

❏

 While turning (RH/LH)

Headlight 

❏

 ON/

❏

 OFF

Rear defogger

❏

 ON/

❏

 OFF

Blower

❏

 ON/

❏

 OFF

Radio

❏

 ON/

❏

 OFF

A/C compressor

❏

 ON/

❏

 OFF

CD/Cassette

❏

 ON/

❏

 OFF

Cooling fan 

❏

 ON/

❏

 OFF 

Car phone 

❏

 ON/

❏

 OFF

Front wiper

❏

 ON/

❏

 OFF

CB

❏

 ON/

❏

 OFF

Rear wiper 

❏

 ON/

❏

 OFF

EN(H4SOw/oOBD)-5

ENGINE (DIAGNOSTICS)

CHECK LIST FOR INTERVIEW

2. CHECK LIST NO. 2

Check the following items about the vehicle's state when MIL turns on.

NOTE:
Use copies of this page for interviewing customers.

a) Other warning lights or indicators turn on. 

❏

 Yes/

❏

 No 

❏

 Low fuel warning light 

❏

 Charge indicator light 

❏

 AT diagnostics indicator light 

❏

 ABS warning light 

❏

 VDC warning light

❏

 Engine oil pressure warning light

b) Fuel level

• Lack of gasoline: 

❏

 Yes/

❏

 No

• Indicator position of fuel gauge: 

c) Intentional connecting or disconnecting of harness connectors or spark plug cords: 

❏

 Yes/

❏

 No

• What:

d) Intentional connecting or disconnecting of hoses: 

❏

 Yes/

❏

 No 

• What:

e) Installing of parts other than genuine parts: 

❏

 Yes/

❏

 No

• What:
• Where: 

f) Occurrence of noise: 

❏

 Yes/

❏

 No

• From where:
• What kind:

g) Occurrence of smell: 

❏

 Yes/

❏

 No

• From where:
• What kind:

h) Intrusion of water into engine compartment or passenger compartment: 

❏

 Yes/

❏

 No

i) Troubles occurred

❏

 Engine does not start. 

❏

 Engine stalls during idling. 

❏

 Engine stalls while driving. 

❏

 Engine speed decreases. 

❏

 Engine speed does not decrease. 

❏

 Rough idling 

❏

 Poor acceleration 

❏

 Back fire 

❏

 After fire 

❏

 No shift 

❏

 Excessive shift shock