Subaru Legacy III (2000-2003 year). Service 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