Subaru Legacy III (2000-2003 year). Manual - part 108

EN(H4SO)-44

ENGINE (DIAGNOSTICS)

INSPECTION MODE

5) Start the engine.

NOTE:
• Ensure the selector lever is placed in the “P” po-
sition before starting. (AT vehicles)
• Depress clutch pedal when starting the engine.
(MT vehicles)
6) Using the selector lever or shift lever, turn the “P”
position switch and the “N” position switch to ON.
7) Depress the brake pedal to turn the brake switch
ON. (AT vehicles)
8) Keep engine speed in the 2,500 — 3,000 rpm
range for 40 seconds.
9) Place the selector lever or shift lever in the “D”
position (AT vehicles) or “1st” gear (MT vehicles)
and drive the vehicle at 5 to 10 km/h (3 to 6 MPH).

NOTE:
• On AWD vehicles, release the parking brake.
• The speed difference between front and rear
wheels may light the ABS warning light, but this in-
dicates no malfunctions. When engine control diag-
nosis is finished, perform the ABS memory
clearance procedure of self-diagnosis system.
10) Using the OBD-II general scan tool, check for
diagnostic trouble code(s) and record the result(s).

NOTE:
• For detailed operation procedures, refer to the
OBD-II General Scan Tool Instruction Manual.
• For detailed concerning diagnostic trouble
codes, refer to the List of Diagnostic Trouble Code
(DTC). 
<Ref. to EN(H4SO)-83, List of Diagnostic Trouble
Code (DTC).>

EN(H4SO)-45

ENGINE (DIAGNOSTICS)

DRIVE CYCLE

13.Drive Cycle

A: OPERATION

There are 3 drive patterns for trouble diagnosis.
Driving in the specified pattern allows to diagnose
the malfunctioning items listed below. After the
malfunctioning items listed below are repaired, al-
ways check whether they correctly resume their
functions by driving in the required drive pattern. 

1. PREPARATION FOR THE DRIVE CYCLE

1) Make sure that fuel remains approx. half amount
[20 to 40 

2

 (5.3 — 10.6 US gal, 4.4 — 8.8 Imp

gal)], and battery voltage is 12V or more.

2) After performing diagnostics and cleaning the
memory, check for any remaining unresolved trou-
ble data. <Ref. to EN(H4SO)-47, Clear Memory
Mode.>
3) Separate test mode connector.

NOTE:
• Except for water temperature specified items at
starting, diagnosis is carried out after engine warm
up.
• Carry out diagnosis which is marked * on DTC
twice, Then, after finishing 1st diagnosis, stop en-
gine and do the second time at the same condition.

2. AFTER RUNNING 20 MINUTES AT 80 KM/H (50 MPH), IDLE ENGINE FOR 1 MINUTE.

3. IDLE FOR 10 MINUTES

NOTE:
Before diagnosis, drive vehicle at 4 km/h (6 MPH) or more.

DTC

No.

Item

Condition

P0030

HO2S Heater control circuit (Bank 1 Sensor 1)

Coolant temperature at start is less than 30

°

C (86

°

F).

*P0111

Intake air temperature circuit range/performance

Coolant temperature at start is less than 30

°

C (86

°

F).

*P0125

Insufficient coolant temperature for closed loop 
fuel control

Coolant temperature at start is less than 20

°

C (68

°

F). 

*P0130

O2 Sensor circuit (Bank 1 Sensor 1)

—

*P0133

O2 Sensor circuit slow response (Bank 1 Sensor 
1)

—

*P0420

Catalyst system efficiency below threshold (Bank 
1)

—

P0459

Evaporative emission control system purge con-
trol valve circuit high

—

*P0461

Fuel level sensor circuit range/performance

—

*P0464

Fuel level sensor circuit intermittent

—

*P1137

O2 Sensor circuit (Bank 1 Sensor 1)

—

DTC No.

Item

Condition 

*P0483

Cooling fan rationality check

—

*P0506

Idle control system RPM lower than expected

—

*P0507

Idle control system RPM higher than expected

—

EN(H4SO)-46

ENGINE (DIAGNOSTICS)

DRIVE CYCLE

4. DRIVE ACCORDING TO THE FOLLOWING DRIVE PATTERN

(A) Idle engine for 1 minute.

(D) Decelerate with fully closed throt-

tle to 64 km/h (40 MPH).

(F) Accelerate to 97 km/h (60 MPH) 

within 10 seconds.

(B) Accelerate to 97 km/h (60 MPH) 

within 20 seconds.

(E) Drive vehicle at 64 km/h (40 MPH) 

for 10 seconds.

(G) Stop vehicle with throttle fully 

closed.

(C) Drive vehicle at 97 km/h (60 MPH) 

for 20 seconds.

DTC No.

Item

Condition

*P0121

Throttle/pedal position sensor/switch “A” circuit range/performance

—

*P0139

O2 Sensor circuit slow response (Bank 1 Sensor 2)

—

*P0171

System too lean (Bank 1)

—

*P0172

System too rich (Bank 1)

—

*P0301

Cylinder 1 misfire detected

—

*P0302

Cylinder 2 misfire detected

—

*P0303

Cylinder 3 misfire detected

—

*P0304

Cylinder 4 misfire detected

—

*P0400

Exhaust gas recirculation flow

—

EN-00195

50

100

150

0

65 (40)

96 (60)

(Seconds)

Vehicle speed km/h (MPH)

( A )

( B )

( C )

( D )

( E )

( F )

( G )

EN(H4SO)-47

ENGINE (DIAGNOSTICS)

CLEAR MEMORY MODE

14.Clear Memory Mode

A: OPERATION

1. SUBARU SELECT MONITOR (NORMAL 
MODE)

1) On the «Main Menu» display screen, select the
{2. Each System Check} and press the [YES] key.
2) On the «System Selection Menu» display
screen, select the {Engine Control System} and
press the [YES] key.
3) Press the [YES] key after displayed the informa-
tion of engine type.
4) On the «Engine Diagnosis» display screen, se-
lect the {Clear Memory} and press the [YES] key.
5) When the `Done' and `Turn Ignition Switch OFF'
are shown on the display screen, turn the Subaru
Select Monitor and ignition switch to OFF.

NOTE:
• After the memory has been cleared, the ISC
must be initialized.  To do this, turn the ignition
switch to the ON position. Wait 3 seconds before
starting the engine.
• For detailed operation procedure, refer to the
SUBARU SELECT MONITOR OPERATION MAN-
UAL.

2. SUBARU SELECT MONITOR (OBD 
MODE)

1) On the «Main Menu» display screen, select the
{2. Each System Check} and press the [YES] key.
2) On the «System Selection Menu» display
screen, select the {Engine Control System} and
press the [YES] key.
3) Press the [YES] key after displayed the informa-
tion of engine type.
4) On the «Engine Diagnosis» display screen, se-
lect the {OBD System} and press the [YES] key.
5) On the «OBD Menu» display screen, select the
{4. Diagnosis Code(s) Cleared} and press the
[YES] key.
6) When the `Clear Diagnostic Code?' is shown on
the display screen, press the [YES] key.
7) Turn Subaru Select Monitor and ignition switch
to OFF.

NOTE:
• After the memory has been cleared, the idle air
control solenoid valve must be initialized.  To do
this, turn the ignition switch to the ON position. Wait
3 seconds before starting the engine.
• For detailed operation procedure, refer to the
SUBARU SELECT MONITOR OPERATION MAN-
UAL.

3. OBD-II GENERAL SCAN TOOL

For clear memory procedures using the OBD-II
general scan tool, refer to the OBD-II General Scan
Tool Instruction Manual.
After the memory has been cleared, the idle air
control solenoid valve must be initialized.  To do
this, turn the ignition switch to the ON position. Wait
3 seconds before starting the engine.