Subaru Legacy III (2000-2003 year). Manual - part 332

EN(H6DO)-130

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

K: DTC P0108 — MANIFOLD ABSOLUTE PRESSURE/BAROMETRIC PRES-

SURE 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(H6DO)-54, OP-
ERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H6DO)-47, OPERATION, Inspec-
tion Mode.>.

• WIRING DIAGRAM:

EN-00811

9

19

8

5

8

B135

B20

E1

16

13

14

B83

E21

1 2 3

B83

B20

B135

ECM

3

2

1

E21

INTAKE MANIFOLD
PRESSURE SENSOR

THROTTLE BODY

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

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

1 2 3 4

5 6 7 8 9 10

11 12

19 20

13 14 15 16 17 18

EN(H6DO)-131

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK CURRENT DATA.
1) Start engine.
2) Read the data of intake manifold absolute 

pressure signal using Subaru Select Moni-
tor or 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(H6DO)-34, Subaru Select Moni-
tor.>
• OBD-II general scan tool
For detailed operation procedures, refer to the 
OBD-II General Scan Tool Instruction Manual.

130 kPa (975 mmHg, 38.39 
inHg)

Go to step 10.

Go to step 2.

2

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

Connector & terminal

(B135) No. 9 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the specified 
value?

4.5 V

Go to step 4.

Go to step 3.

3

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

Connector & terminal

(B135) No. 9 (+) — Chassis ground (

−−−−

):

Does the voltage change more than the speci-
fied value by shaking harness and connector 
of ECM while monitoring the value with voltage 
meter?

4.5 V

Repair poor con-
tact in ECM con-
nector.

Contact SUBARU 
distributor service.

NOTE:
Inspection by DTM
is required, be-
cause probable
cause is deteriora-
tion of multiple
parts.

4

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

Connector & terminal

(B135) No. 8 (+) — Chassis ground (

−−−−

):

Is the measured value less than the specified 
value?

0.7 V

Go to step 6.

Go to step 5.

5

CHECK INPUT SIGNAL FOR ECM.
Read data of intake manifold atmospheric 
absolute pressure signal using Subaru Select 
Monitor.
Does the value change more than  the speci-
fied value by shaking harness and connector 
of ECM while monitoring the value with Subaru 
Select Monitor?

NOTE:

• Subaru Select Monitor
For detailed operation procedure, refer to the 
“READ CURRENT DATA FOR ENGINE”. 
<Ref. to EN(H6DO)-34, Subaru Select Moni-
tor.>

1.7 kPa (13 mmHg, 0.51 inHg) Repair poor con-

tact in ECM con-
nector.

Go to step 6.

EN(H6DO)-132

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

6

CHECK HARNESS BETWEEN ECM AND IN-
TAKE MANIFOLD PRESSURE SENSOR 
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from intake manifold 

pressure sensor.

3) Turn ignition switch to ON.
4) Measure voltage between intake manifold 

pressure sensor connector and engine 
ground.

Connector & terminal

(E21) No. 3 (+) — Engine ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

4.5 V

Go to step 7.

Repair open circuit 
in harness 
between ECM and 
intake manifold 
pressure sensor 
connector.

7

CHECK HARNESS BETWEEN ECM AND IN-
TAKE MANIFOLD PRESSURE SENSOR 
CONNECTOR.
1) Turn ignition switch to OFF.
2) Disconnect connector from ECM.
3) Measure resistance of harness between 

ECM and intake manifold pressure sensor 
connector.

Connector & terminal

(B135) No. 8 — (E21) No. 1:

Is the measured value less than the speci-
fied value?

1 

Ω

Go to step 8.

Repair open circuit 
in harness 
between ECM and 
intake manifold 
pressure sensor 
connector.

8

CHECK HARNESS BETWEEN ECM AND IN-
TAKE MANIFOLD PRESSURE SENSOR 
CONNECTOR.
Measure resistance of harness between ECM 
and intake manifold pressure sensor connec-
tor.

Connector & terminal

(B135) No. 19 — (E21) No. 2:

Is the measured value less than the specified 
value?

1 

Ω

Go to step 9.

Repair open circuit 
in harness 
between ECM and 
intake manifold 
pressure sensor 
connector.

9

CHECK POOR CONTACT.
Check poor contact in intake manifold pressure 
sensor connector. 
Is there poor contact in intake manifold pres-
sure sensor connector?

There is poor contact.

Repair poor con-
tact in intake mani-
fold pressure 
sensor connector.

Replace intake 
manifold pressure 
sensor. <Ref. to 
FU(H6DO)-34, 
Intake Manifold 
Pressure Sensor.>

Step

Value

Yes

No

EN(H6DO)-133

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

10

CHECK HARNESS BETWEEN ECM AND 
PRESSURE SENSOR CONNECTOR.
1) Turn ignition switch to OFF and Subaru 

Select Monitor or the OBD-II general scan 
tool switch to OFF.

2) Disconnect connector from pressure sen-

sor.

3) Turn ignition switch to ON and Subaru 

Select Monitor or the OBD-II general scan 
tool switch to ON.

4) Read data of intake manifold absolute pres-

sure signal using Subaru Select Monitor or 
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(H6DO)-34, Subaru Select Moni-
tor.>
• OBD-II general scan tool
For detailed operation procedures, refer to the 
OBD-II General Scan Tool Instruction Manual.

130 kPa (975 mmHg, 38.39 
inHg)

Repair battery 
short circuit in har-
ness between 
ECM and intake 
manifold pressure 
sensor connector.

Replace intake 
manifold pressure 
sensor. <Ref. to 
FU(H6DO)-34, 
Intake Manifold 
Pressure Sensor.>

Step

Value

Yes

No