Subaru Legacy (2005 year). Service manual — part 329

EN(H4DOTC)(diag)-85

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

I:

DTC P0112 INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT LOW

DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
• Erroneous idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-03523

B3

E

B83

1

B3

ECM

B136

SBF-7

1 2 3 4 5

3

4

1

2

5

6

B136

B47

*

*

2

4

3

5

31

13

23

35

32

B47

1

2

4

6

3

5

1 2 3 4
5 6 7 8

B83

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

33 34

29

32

30

31

35

BATTERY

MASS AIR FLOW AND

INTAKE AIR TEMPERATURE

SENSOR

MAIN RELAY

*

: TERMINAL No. RANDOM ARRANGEMENT

EN(H4DOTC)(diag)-86

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake air temperature
sensor signal using Subaru Select Monitor or
general scan tool.

NOTE:

• Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-24, Subaru Select Mon-
itor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.

Is the temperature more than
55

°C (131°F)?

Go to step 2.

Repair the poor
contact.

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

2

CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from mass air
flow and intake air temperature sensor.
3) Turn the ignition switch to ON.
4) Read the data of intake air temperature
sensor signal using Subaru Select Monitor or
general scan tool.

NOTE:

• Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-24, Subaru Select Mon-
itor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.

Is the temperature less than
−36°C (−33°F)?

Replace the mass
air flow and intake
air temperature
sensor. <Ref. to
FU(H4DOTC)-27,
Mass Air Flow and
Intake Air Temper-
ature Sensor.>

Repair the ground
short circuit of har-
ness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector.

EN(H4DOTC)(diag)-87

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

J: DTC P0113 INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT HIGH

DTC DETECTING CONDITION:
Immediately at fault recognition
TROUBLE SYMPTOM:
• Erroneous idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
37, OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOTC)(diag)-30, PROCE-
DURE, Inspection Mode.>.
WIRING DIAGRAM:

EN-03523

B3

E

B83

1

B3

ECM

B136

SBF-7

1 2 3 4 5

3

4

1

2

5

6

B136

B47

*

*

2

4

3

5

31

13

23

35

32

B47

1

2

4

6

3

5

1 2 3 4
5 6 7 8

B83

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

33 34

29

32

30

31

35

BATTERY

MASS AIR FLOW AND

INTAKE AIR TEMPERATURE

SENSOR

MAIN RELAY

*

: TERMINAL No. RANDOM ARRANGEMENT

EN(H4DOTC)(diag)-88

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake air temperature
sensor signal using Subaru Select Monitor or
general scan tool.

NOTE:

• Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-24, Subaru Select Mon-
itor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.

Is the temperature less than
−36°C (−33°F)?

Go to step 2.

Repair the poor
contact.

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

2

CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from mass air
flow and intake air temperature sensor.
3) Measure the voltage between mass air flow
and intake air temperature sensor connector
and engine ground.

Connector & terminal

(B3) No. 4 (+) — Engine ground (

−

):

Is the voltage more than 10 V? Repair the battery

short circuit of har-
ness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector.

Go to step 3.

3

CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between mass air flow
and intake air temperature sensor connector
and engine ground.

Connector & terminal

(B3) No. 4 (+) — Engine ground (

−

):

Is the voltage more than 10 V? Repair the battery

short circuit of har-
ness between
mass air flow and
intake air tempera-
ture sensor and
ECM connector.

Go to step 4.

4

CHECK HARNESS BETWEEN MASS AIR
FLOW AND INTAKE AIR TEMPERATURE
SENSOR AND ECM CONNECTOR.
Measure the voltage between mass air flow
and intake air temperature sensor connector
and engine ground.

Connector & terminal

(B3) No. 4 (+) — Engine ground (

−

):

Is the voltage more than 4 V?

Go to step 5.

Repair the har-
ness and connec-
tor.

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