Subaru Legacy III (2000-2003 year). Manual - part 495

EN(H4DOSTC)-150

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

5

CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE.
1) Turn the ignition switch to ON.
2) Measure the voltage between purge control 

solenoid valve and engine ground.

Connector & terminal

(E4) No. 1 (+) — Engine ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 6.

Repair the open 
circuit in harness 
between main 
relay and purge 
control solenoid 
valve connector.

6

CHECK POOR CONTACT.
Check poor contact in purge control solenoid 
valve connector.
Is there poor contact in purge control solenoid 
valve connector?

There is poor contact.

Repair the poor 
contact in purge 
control solenoid 
valve connector.

Contact SUBARU 
distributor service.

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

Step

Value

Yes

No

EN(H4DOSTC)-151

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H4DOSTC)-152

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AF:DTC P0445 — EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CON-

TROL VALVE CIRCUIT SHORTED —

• TROUBLE SYMPTOM:

• Erroneous idling

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-00945

MAIN  RELAY

B47

1

2

3

5

4

6

BATTERY

E

E3

B47

B137

B137

E4

PURGE  CONTROL
SOLENOID  VALVE

ECM

16

2

1

SBF-5

3

4

1

2

5

6

1

2

7

8

9

5

6

3

4

10 11 12

19 20 21
29 30 31

13 14 15 16 17

27 28

18

22 23 24 25 26

2

1

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

B22

E4

1 2

B22

EN(H4DOSTC)-153

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to OFF.
2) Connect the test mode connector at the 

lower portion of instrument panel (on the 
driver's side), to the side of center console 
box.

3) Turn the ignition switch to ON.
4) While operating the purge control solenoid 

valve, measure the voltage between ECM 
and chassis ground.

NOTE:

Purge control solenoid valve operation can be
executed using the Subaru Select Monitor. For
procedure, refer to “Compulsory Valve Opera-
tion Check Mode”. <Ref. to EN(H4DOSTC)-36,
Compulsory Valve Operation Check Mode.>  

Connector & terminal

(B137) No. 16 (+) — Chassis ground (

−−−−

):

Is the measured value within the specified 
value?

0 — 13 V

Go to step 2.

Even if MI light up, 
the circuit has 
returned to a nor-
mal condition at 
this time. In this 
case, repair the 
poor contact in 
ECM connector.

2

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM and 

chassis ground.

Connector & terminal

(B137) No. 16 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Go to step 4.

Go to step 3.

3

CHECK POOR CONTACT.
Check poor contact in ECM connector. 
Is there poor contact in ECM connector?

There is poor contact.

Repair the poor 
contact in ECM 
connector.

Replace the ECM.  
<Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

4

CHECK HARNESS BETWEEN PURGE CON-
TROL SOLENOID VALVE AND ECM CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from purge con-

trol solenoid valve.

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

chassis ground.

Connector & terminal

(B137) No. 16 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Repair the battery 
short circuit in har-
ness between 
ECM and purge 
control solenoid 
valve connector. 
After repair, 
replace the ECM.  
<Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

Go to step 5.

5

CHECK PURGE CONTROL SOLENOID 
VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between purge 

control solenoid valve terminals.

Terminals

No. 1 — No. 2:

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

1 

Ω

Replace the purge 
control solenoid 
valve  <Ref. to 
EC(H4DOSTC)-6, 
Purge Control 
Solenoid Valve.> 
and ECM  <Ref. to 
FU(H4DOSTC)-
40, Engine Con-
trol Module.>

Go to step 6.