Subaru Legacy (2005 year). Manual - part 203

EN(H4SO 2.5)(diag)-97

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

8

CHECK HARNESS BETWEEN ECM AND 
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from manifold 
absolute pressure sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between manifold 
absolute pressure sensor connector and 
engine ground.

Connector & terminal

(E21) No. 3 (+) — Engine ground (

−

):

Is the voltage more than 4.5 V? Go to step 9.

Repair the open 
circuit of harness 
between ECM and 
manifold absolute 
pressure sensor 
connector.

9

CHECK HARNESS BETWEEN ECM AND 
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness 
between ECM and manifold absolute pressure 
sensor connector.

Connector & terminal

(B136) No. 35 — (E21) No. 2:

Is the resistance less than 1 
Ω?

Go to step 10.

Repair the open 
circuit of harness 
between ECM and 
manifold absolute 
pressure sensor 
connector.

10

CHECK POOR CONTACT.
Check poor contact in manifold absolute pres-
sure sensor connector.

Is there poor contact in mani-
fold absolute pressure sensor 
connector?

Repair the poor 
contact in mani-
fold absolute pres-
sure sensor 
connector.

Replace the mani-
fold absolute pres-
sure sensor. <Ref. 
to FU(H4SO 2.5)-
25, Manifold Abso-
lute Pressure Sen-
sor.>

Step

Check

Yes

No

EN(H4SO 2.5)(diag)-98

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

I:

DTC P0108 MANIFOLD ABSOLUTE PRESSURE/BAROMETRIC PRESSURE 
CIRCUIT HIGH INPUT

DTC DETECTING CONDITION:
Immediately at fault recognition

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4SO 2.5)(diag)-
40, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO 2.5)(diag)-33, Inspection Mode.>.
WIRING DIAGRAM:
• EC, EK, EH, ER and K4 model

• KA and KS model

NOTE:
Fuel injection system for KA and KS model is the same as 2.0 L model. Refer to EN(H4SO 2.0) section.

EN-03460

35

22

16

MANIFOLD

ABSOLUTE
PRESSURE

SENSOR

19

20

7

B21

E2

2

3

1

E21

ECM

B21

B136

2

2

1 2 3 4
5 6 7 8

B122

B138

B83

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

B136

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

*

: TERMINAL No. RANDOM ARRANGEMENT

E21

B122 : RHD

B138 : LHD

B83

1 2 3

*

*

1

1

1

*

: TERMINAL No. RANDOM ARRANGEMENT
  AMONG 1,2,5, AND 6

2

*

*

EN(H4SO 2.5)(diag)-99

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK OPTION CODE.

Is the option code EC, EK, EH, 
ER or K4?

Go to step 2.

Refer to EN(H4SO 
2.0) section. <Ref. 
to EN(H4SO 
2.0)(diag)-64, List 
of Diagnostic Trou-
ble Code (DTC).>

NOTE:
Fuel injection sys-
tem for KA and KS
model is the same
as 2.0 L model.

2

CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector 
and chassis ground.

Connector & terminal

(B136) No. 16 (+) — Chassis ground (

−

):

Is the voltage more than 4.5 V? Go to step 4.

Go to step 3.

3

CHECK OUTPUT SIGNAL FROM ECM.
Measure the voltage between ECM connector 
and chassis ground.

Connector & terminal

(B136) No. 16 (+) — Chassis ground (

−

):

Does the voltage change by 
shaking the ECM harness and 
connector?

Repair the poor 
contact in ECM 
connector.

Replace the ECM. 
<Ref. to FU(H4SO 
2.5)-37, Engine 
Control Module 
(ECM).>

4

CHECK INPUT SIGNAL OF ECM.
Measure the voltage between ECM connector 
and chassis ground.

Connector & terminal

(B136) No. 22 (+) — Chassis ground (

−

):

Is the voltage more than 4.5 V? Go to step 6.

Go to step 5.

5

CHECK INPUT SIGNAL OF ECM (USING 
SUBARU SELECT MONITOR).
Read the data of atmospheric absolute pres-
sure signal using Subaru Select Monitor.

NOTE:

For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4SO 2.5)(diag)-25, Subaru Select Mon-
itor.>

Is the value more than 13.3 
kPa (100 mmHg, 3.94 inHg) 
when shaking the ECM har-
ness and connector?

Repair the poor 
contact in ECM 
connector.

Go to step 6.

6

CHECK HARNESS BETWEEN ECM AND 
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from manifold 
absolute pressure sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between manifold 
absolute pressure sensor connector and 
engine ground.

Connector & terminal

(E21) No. 3 (+) — Engine ground (

−

):

Is the voltage more than 4.5 V? Go to step 7.

Repair the open 
circuit of harness 
between ECM and 
manifold absolute 
pressure sensor 
connector.

7

CHECK HARNESS BETWEEN ECM AND 
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ECM.
3) Measure the resistance of harness 
between ECM and manifold absolute pressure 
sensor connector.

Connector & terminal

(B136) No. 22 — (E21) No. 1:

Is the resistance less than 1 
Ω?

Go to step 8.

Repair the open 
circuit of harness 
between ECM and 
manifold absolute 
pressure sensor 
connector.

EN(H4SO 2.5)(diag)-100

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

8

CHECK HARNESS BETWEEN ECM AND 
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground.

Connector & terminal

(B136) No. 22 (+) — Chassis ground (

−

):

Is the voltage more than 4.5 V? Repair the short 

circuit of harness 
between ECU and 
manifold absolute 
pressure sensor 
connector.

Go to step 9.

9

CHECK HARNESS BETWEEN ECM AND 
MANIFOLD ABSOLUTE PRESSURE SEN-
SOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance of harness 
between ECM and manifold absolute pressure 
sensor connector.

Connector & terminal

(B136) No. 35 — (E21) No. 2:

Is the resistance less than 1 
Ω?

Go to step 10.

Repair the open 
circuit of harness 
between ECM and 
manifold absolute 
pressure sensor 
connector.

10

CHECK POOR CONTACT.
Check poor contact in manifold absolute pres-
sure sensor connector.

Is there poor contact in mani-
fold absolute pressure sensor 
connector?

Repair the poor 
contact in mani-
fold absolute pres-
sure sensor 
connector.

Replace the mani-
fold absolute pres-
sure sensor. <Ref. 
to FU(H4SO 2.5)-
25, Manifold Abso-
lute Pressure Sen-
sor.>

Step

Check

Yes

No