Subaru Legacy III (2000-2003 year). Manual - part 125

EN(H4SO)-112

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

6

CHECK HARNESS BETWEEN ECM AND 
PRESSURE SENSOR CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from pressure sen-

sor.

3) Turn ignition switch to ON.
4) Measure voltage between pressure sensor 

connector and engine ground.

Connector & terminal

(E21) No. 3 (+) — Engine ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

4.5 V

Go to step 7.

Repair open circuit 
in harness 
between ECM and 
pressure sensor 
connector.

7

CHECK HARNESS BETWEEN ECM AND 
PRESSURE SENSOR CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between 

ECM and pressure sensor connector.

Connector & terminal

(B135) No. 15 — (E21) No. 2:
(B135) No. 1 — (E21) No. 1:

Is the measured value less than the speci-
fied value?

1 

Ω

Go to step 8.

Repair open circuit 
in harness 
between ECM and  
pressure sensor 
connector.

8

CHECK POOR CONTACT.
Check poor contact in pressure sensor con-
nector. 
Is there poor contact in pressure sensor con-
nector?

There is poor contact.

Repair poor con-
tact in pressure 
sensor connector.

Replace pressure 
sensor. <Ref. to 
FU(H4SO)-32, 
Pressure Sensor.>

9

CHECK HARNESS BETWEEN ECM AND 
PRESSURE SENSOR CONNECTOR.
1) Turn ignition switch to OFF and Subaru 

Select Monitor or the OBD-II general scan 
tool switch to OFF.

2) Disconnect connector from pressure sen-

sor.

3) Turn ignition switch to ON and Subaru 

Select Monitor or the OBD-II general scan 
tool switch to ON.

4) Read data of intake manifold absolute pres-

sure signal using Subaru Select Monitor or 
OBD-II general scan tool.
Does the measured value exceed the spec-
ified value?

NOTE:

•Subaru Select Monitor
For detailed operation procedure, refer to the 
“READ CURRENT DATA FOR ENGINE”. 
<Ref. to EN(H4SO)-32, Subaru Select Moni-
tor.>  
•OBD-II general scan tool
For detailed operation procedures, refer to the 
OBD-II General Scan Tool Instruction Manual.

119.5 kPa (896.5 mmHg, 
35.29 inHg)

Repair battery 
short circuit in har-
ness between 
ECM and pressure 
sensor connector.

Replace pressure 
sensor. <Ref. to 
FU(H4SO)-32, 
Pressure Sensor.>

Step

Value

Yes

No

EN(H4SO)-113

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H4SO)-114

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

I:

DTC P0111 — INTAKE AIR TEMPERATURE CIRCUIT RANGE/PERFOR-
MANCE —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Erroneous idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode<Ref. to EN(H4SO)-47, OPER-
ATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-01124

D6

B19

INTAKE AIR

TEMPERATURE

SENSOR

B135

14

9

B21

E2

1

2

E20

B21

ECM

B:

B137

D:

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

E20

1 2

B137

4

1
5

3

2
6

18

15

16

7 8 9 10 11

17

19 20

12 13

14

5 6 7

8

2

1

9

4

3

10

24

22 23

25

11 12 13 14 15

26

27 28

16 17 18 19

20 21

B135

B83

3

1

FG

2

4

EG

: FOR G.C.C COUNTRIES MODEL 

: EXCEPT FOR G.C.C COUNTRIES MODEL 

FG

EG

B83

1 2 3 4 5 6

EN(H4SO)-115

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK ANY OTHER DTC ON DISPLAY.
Is any other DTC displayed?

DTC indicated.

Inspect the rele-
vant DTC using 
“List of Diagnostic 
Trouble Code 
(DTC)”. <Ref. to 
EN(H4SO)-83, List 
of Diagnostic 
Trouble Code 
(DTC).>  

NOTE:
In this case, it is
not necessary to
inspect DTC
P0111.

Go to step 2.

2

CHECK ENGINE COOLANT TEMPERA-
TURE.
1) Start the engine and warm it up completely.
2) Measure engine coolant temperature using 

Subaru Select Monitor or OBD-II general 
scan tool.
Is the measured value within the specified 
range?

NOTE:

•Subaru Select Monitor
For detailed operation procedure, refer to the 
“READ CURRENT DATA FOR ENGINE”. 
<Ref. to EN(H4SO)-32, Subaru Select Moni-
tor.>
•OBD-II general scan tool
For detailed operation procedures, refer to the 
OBD-II General Scan Tool Instruction Manual.

75 - 95

°

C (167 - 203

°

F) Replace 

intake 

air 

temperature sen-
sor. <Ref. to 
FU(H4SO)-33, 
REMOVAL, Intake 
Air Temperature 
Sensor.>

Inspect DTC 
P0125 using “List 
of Diagnostic 
Trouble Code 
(DTC)”. <Ref. to 
EN(H4SO)-83, List 
of Diagnostic 
Trouble Code 
(DTC).>