Subaru Legacy IV (2008 year). Manual - part 541

EN(H6DO)(diag)-137

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AA:DTC P0111 INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT RANGE/

PERFORMANCE

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-37, DTC P0111 INTAKE AIR TEMPERATURE SENSOR
1 CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Improper idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-03920

B83

B3

BATTERY

E

B83

1

B3

MASS AIR FLOW & INTAKE 
AIR TEMPERATURE  SENSOR

ECM

B135

SBF-7

1 2 3 4 5

3

4

1

2

5

6

B135

B47

*

*

2

4

3

5

34

18

26

30

35

MAIN RELAY

B47

1

2

4

6

3

5

1 2 3 4
5 6 7 8

*

 : TERMINAL No. 
    OPTIONAL ARRANGEMENT

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

29 30 31

32 33

34 35

EN(H6DO)(diag)-138

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK ENGINE COOLANT TEMPERA-
TURE.
1) Start the engine and warm up completely.
2) Measure the engine coolant temperature 
using the 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(H6DO)(diag)-34, Subaru Select Moni-
tor.>
• General Scan Tool
For detailed operation procedures, refer to the
general scan tool operation manual.

Is the engine coolant tempera-
ture 75°C (167°F) or higher?

Replace the mass 
air flow and intake 
air temperature 
sensor. <Ref. to 
FU(H6DO)-26,
Mass Air Flow and 
Intake Air Temper-
ature Sensor.>

Check DTC P0125 
using “List of Diag-
nostic Trouble 
Code (DTC)”. 
<Ref. to 
EN(H6DO)(diag)-
81, List of Diagnos-
tic Trouble Code 
(DTC).>

EN(H6DO)(diag)-139

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AB:DTC P0112 INTAKE AIR TEMPERATURE SENSOR 1 CIRCUIT LOW

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H6DO)-39, DTC P0112 INTAKE AIR TEMPERATURE SENSOR
1 CIRCUIT LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Improper idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H6DO)(diag)-52,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H6DO)(diag)-44, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-03920

B83

B3

BATTERY

E

B83

1

B3

MASS AIR FLOW & INTAKE 
AIR TEMPERATURE  SENSOR

ECM

B135

SBF-7

1 2 3 4 5

3

4

1

2

5

6

B135

B47

*

*

2

4

3

5

34

18

26

30

35

MAIN RELAY

B47

1

2

4

6

3

5

1 2 3 4
5 6 7 8

*

 : TERMINAL No. 
    OPTIONAL ARRANGEMENT

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

29 30 31

32 33

34 35

EN(H6DO)(diag)-140

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK CURRENT DATA.
1) Start the engine.
2) Read the data of intake air temperature sen-
sor signal using Subaru Select Monitor or gen-
eral scan tool.

NOTE:
• SUBARU SELECT MONITOR
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-34, Subaru Select Moni-
tor.>
• General Scan Tool
For detailed operation procedures, refer to the
general scan tool operation manual.

Is the intake air temperature 
120°C (248°F) or higher?

Go to step 2.

Even if DTC is 
detected, the cir-
cuit has returned to 
a normal condition 
at this time. Repro-
duce the failure, 
and then perform 
the diagnosis 
again.

NOTE:
In this case, tem-
porary poor con-
tact of connector
may be the cause.

2

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

Connector & terminal

(B135) No. 18 — Chassis ground:

Is the resistance 1 M

: or 

more?

Replace the mass 
air flow and intake 
air temperature 
sensor. <Ref. to 
FU(H6DO)-26,
Mass Air Flow and 
Intake Air Temper-
ature Sensor.>

Repair the ground 
short circuit of har-
ness between the 
ECM and the mass 
air flow and intake 
air temperature 
sensor connectors.