Subaru Legacy IV (2008 year). Manual - part 140

EN(H4SO)(diag)-163

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 fuel temperature sensor 
signal using Subaru Select Monitor.

NOTE:
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4SO)(diag)-33, Subaru Select Moni-
tor.>

Is the temperature less than 
–40°C (–40°F)?

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 POOR CONTACT.
Repair any poor contact between the ECM and 
fuel temperature sensor connectors.

Is there poor contact in the 
ECM or fuel temperature sen-
sor connectors?

Repair any poor 
contact between 
the ECM and fuel 
temperature sen-
sor connectors.

Go to step 3.

3

CHECK HARNESS BETWEEN ECM AND 
FUEL TEMPERATURE SENSOR CONNEC-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM and 
fuel temperature sensor.
3) Measure the resistance of the harness 
between the ECM and fuel temperature sensor 
connector.

Connector & terminal

(B135) No. 17 — (R58) No. 2:
(B135) No. 30 — (R58) No. 3:

Is the resistance less than 1 

:? Go to step 4.

Repair the harness 
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and fuel tem-
perature sensor
connector
• Poor contact of
coupling connector
• Poor contact in
joint connector

4

CHECK HARNESS BETWEEN ECM AND 
FUEL TEMPERATURE SENSOR CONNEC-
TOR.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Measure the voltage between ECM and 
chassis ground.

Connector & terminal

(B135) No. 17 (+) — Chassis ground (–):

Is the voltage 5 V or more?

Repair the short 
circuit to power in 
the harness 
between the ECM 
and fuel tempera-
ture sensor con-
nector.

Replace the fuel 
temperature sen-
sor. <Ref. to 
EC(H4SO)-10,
Fuel Temperature 
Sensor.>

EN(H4SO)(diag)-164

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AO:DTC P0196 ENGINE OIL TEMPERATURE SENSOR CIRCUIT RANGE/

PERFORMANCE

DTC DETECTING CONDITION:
• Two consecutive driving cycles with fault
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-73, DTC P0196 ENGINE OIL TEMPERATURE SENSOR
CIRCUIT RANGE/PERFORMANCE, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Hard to start
• Improper idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4SO)(diag)-50,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-41, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-04036

E75

E2

B21

B134

ECM

1

29

2

23

E75

1 2

B21

1 2 3 4

12 13 14 15

5 6 7 8

16 17 18 19

9 10 11

20 21 22

23 24 25 26 27 28 29 30 31 32 33

35

34

37

36

39

38

41

40

43

42

44

45

47

46

49

48

51

50

53

52

54

B134

OIL

TEMPERATURE

SENSOR

19

6

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

EN(H4SO)(diag)-165

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

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

Check the appro-
priate DTC using 
the “List of Diag-
nostic Trouble 
Code (DTC)”. 
<Ref. to 
EN(H4SO)(diag)-
80, List of Diagnos-
tic Trouble Code 
(DTC).>

Replace the oil 
temperature sen-
sor. <Ref. to 
FU(H4SO)-34, Oil 
Temperature Sen-
sor.>

EN(H4SO)(diag)-166

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

AP:DTC P0197 ENGINE OIL TEMPERATURE SENSOR LOW

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4SO)-75, DTC P0197 ENGINE OIL TEMPERATURE SENSOR
LOW, Diagnostic Trouble Code (DTC) Detecting Criteria.>
TROUBLE SYMPTOM:
• Hard to start
• Improper idling
• Poor driving performance

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4SO)(diag)-50,
OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4SO)(diag)-41, PROCEDURE,
Inspection Mode.>.
WIRING DIAGRAM:

EN-04036

E75

E2

B21

B134

ECM

1

29

2

23

E75

1 2

B21

1 2 3 4

12 13 14 15

5 6 7 8

16 17 18 19

9 10 11

20 21 22

23 24 25 26 27 28 29 30 31 32 33

35

34

37

36

39

38

41

40

43

42

44

45

47

46

49

48

51

50

53

52

54

B134

OIL

TEMPERATURE

SENSOR

19

6

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