Subaru Legacy III (2000-2003 year). Manual - part 126

EN(H4SO)-116

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

J: DTC P0112 — INTAKE AIR TEMPERATURE CIRCUIT LOW INPUT —

• DTC DETECTING CONDITION:

• Immediately at fault recognition

• 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)-117

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK CURRENT DATA.
1) Start engine.
2) Read data of intake air temperature sensor 

signal using Subaru Select Monitor or the 
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 procedure, refer to the 
OBD-II General Scan Tool Instruction Manual.

120

°

C (248

°

F)

Go to step 2.

Repair poor con-
tact.

NOTE:
In this case, repair
the following:
• Poor contact in 
intake air tempera-
ture sensor
• Poor contact in 
ECM
• Poor contact in 
coupling connector
• Poor contact in 
joint connector

2

CHECK HARNESS BETWEEN INTAKE AIR 
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from intake air tem-

perature and pressure sensor.

3) Turn ignition switch to ON.
4) Read data of intake air temperature sensor 

signal using Subaru Select Monitor or the 
OBD-II general scan tool.
Is the measured value less than the speci-
fied 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 procedure, refer to the 
OBD-II General Scan Tool Instruction Manual.

−

40

°

C (

−

40

°

F)

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

Repair ground 
short circuit in har-
ness between 
intake air tempera-
ture sensor and 
ECM connector.

EN(H4SO)-118

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

K: DTC P0113 — INTAKE AIR TEMPERATURE CIRCUIT HIGH INPUT —

• DTC DETECTING CONDITION:

• Immediately at fault recognition

• 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)-119

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK CURRENT DATA.
1) Start engine.
2) Read data of intake air temperature sensor 

signal using Subaru Select Monitor or the 
OBD-II general scan tool.
Is the measured value less than the speci-
fied 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 procedure, refer to the 
OBD-II General Scan Tool Instruction Manual.

−

40

°

C (

−

40

°

F)

Go to step 2.

Repair poor con-
tact.

NOTE:
In this case, repair
the following:
• Poor contact in 
intake air tempera-
ture sensor
• Poor contact in 
ECM
• Poor contact in 
coupling connector
• Poor contact in 
joint connector

2

CHECK HARNESS BETWEEN INTAKE AIR 
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from intake air tem-

perature sensor.

3) Measure voltage between intake air tem-

perature sensor connector and engine 
ground.

Connector & terminal

(E20) No. 1 (+) — Engine ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Repair battery 
short circuit in har-
ness between 
intake air tempera-
ture sensor and 
ECM connector.

Go to step 3.

3

CHECK HARNESS BETWEEN INTAKE AIR 
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
1) Turn ignition switch to ON.
2) Measure voltage between intake air tem-

perature sensor connector and engine 
ground.

Connector & terminal

(E20) No. 1 (+) — Engine ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Repair battery 
short circuit in har-
ness between 
intake air tempera-
ture sensor and 
ECM connector.

Go to step 4.

4

CHECK HARNESS BETWEEN INTAKE AIR 
TEMPERATURE SENSOR AND ECM CON-
NECTOR.
Measure voltage between intake air tempera-
ture and pressure sensor connector and 
engine ground.

Connector & terminal

(E20) No. 1 (+) — Engine ground (

−−−−

):

Does the measured value exceed the specified 
value?

3 V

Go to step 5.

Repair harness 
and connector.

NOTE:
In this case, repair
the following:
• Open circuit in 
harness between 
intake air tempera-
ture sensor and 
ECM connector
• Poor contact in 
intake air tempera-
ture sensor
• Poor contact in 
ECM
• Poor contact in 
coupling connector
• Poor contact in 
joint connector