Subaru Legacy III (2000-2003 year). Manual - part 479

EN(H4DOSTC)-86

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

7

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

between ECM and intake manifold pres-
sure sensor connector.

Connector & terminal

(B135) No. 19 — (E21) No. 2:

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

1 

Ω

Go to step 8.

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

8

CHECK HARNESS BETWEEN ECM AND 
PRESSURE SENSOR CONNECTOR.
Measure the resistance of harness between 
intake manifold pressure sensor connector and 
engine ground.

Connector & terminal

(E21) No. 1 — Engine ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 9.

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

9

CHECK POOR CONTACT.
Check poor contact in pressure sensor con-
nector.
Is there poor contact in pressure sensor con-
nector?

There is poor contact.

Repair the poor 
contact in pres-
sure sensor con-
nector.

Replace the pres-
sure sensor. <Ref. 
to FU(H4DOSTC)-
34, Pressure Sen-
sor.>

Step

Value

Yes

No

EN(H4DOSTC)-87

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H4DOSTC)-88

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

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

SURE CIRCUIT HIGH INPUT —

CAUTION:
After repair or replacement of faulty parts, conduct Clear Memory Mode <Ref. to EN(H4DOSTC)-35, 
OPERATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4DOSTC)-33, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-00935

B122

PRESSURE  SENSOR

THROTTLE  BODY

3

2

1

19

9

8

ECM

B135

E21

E2

B21

1
6

20

18

16

1 2 3

B122

B21

E21

1 2 3 4 5 6

1 2

5

6 7

8

13

14 15

16

9 10

11 12

3 4

17 18

19 20

B135

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

EN(H4DOSTC)-89

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

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

pressure signal using Subaru Select Moni-
tor.
Does the measured value exceed the spec-
ified value?

NOTE:

For detailed operation procedure, refer to the
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOSTC)-26, Subaru Select Monitor.>

282 kPa (2121 mmHg, 83.50 
inHg)

Go to step 7.

Go to step 2.

2

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

Connector & terminal

(B135) No. 9 (+) — Chassis ground (

−−−−

):

Does the measured value change by shaking 
harness and connector of ECM while monitor-
ing the value with voltage meter?

The value changes.

Repair the poor 
contact in ECM 
connector.

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 the voltage between ECM connector 
and chassis ground.

Connector & terminal

(B135) No. 8 (+) — Chassis ground (

−−−−

):

Is the measured value less than the specified 
value?

4.5 V

Go to step 5.

Contact SUBARU 
distributor service.

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

5

CHECK HARNESS BETWEEN ECM AND 
PRESSURE SENSOR CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from  pressure 

sensor.

3) Turn the ignition switch to ON.
4) Measure the voltage between 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 6.

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