Subaru Legacy III (2000-2003 year). Manual - part 358

EN(H6DO)-234

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

5

CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE.
1) Turn ignition switch to ON.
2) Measure 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 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 poor con-
tact in purge con-
trol 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(H6DO)-235

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO:

EN(H6DO)-236

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

BA:DTC P0459 — EVAPORATIVE EMISSION CONTROL SYSTEM PURGE CON-

TROL VALVE CIRCUIT HIGH —

• DTC DETECTING CONDITION:

• Two consecutive driving cycles with fault

• TROUBLE SYMPTOM:

• Erroneous idling

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-01092

16

B20

E1

PURGE CONTROL

SOLENOID VALVE

2

1

2

2

4

E4

SBF-5

B137

B20

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

E4

1 2

B47

3

4

1

2

5

6

BATTERY

B137

ECM

B47

B108

F46

MAIN RELAY

2
1

3

5

4

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

RHD

LHD

RHD

LHD

F46

3 4

1 2

EN(H6DO)-237

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

Step

Value

Yes

No

1

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn ignition switch to OFF.
2) Connect test mode connector.
3) Turn ignition switch to ON.
4) While operating purge control solenoid 

valve, measure voltage between ECM and 
chassis ground.

NOTE:

Purge control solenoid valve operation can be
executed using Subaru Select Monitor. For pro-
cedure, refer to “Compulsory Valve Operation
Check Mode”. <Ref. to EN(H6DO)-55, Compul-
sory Valve Operation Check Mode.>  

Connector & terminal

(B137) No. 16 (+) — Chassis ground (

−−−−

):

Does the measured value change within 
the specified range?

0 — 10 V

Go to step 2.

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

2

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

sis ground.

Connector & terminal

(B137) No. 16 (+) — Chassis ground (

−−−−

):

Is the measured value within the specified 
range?

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 poor con-
tact in ECM con-
nector.

Replace ECM. 
<Ref. to 
FU(H6DO)-46, 
Engine Control 
Module.>

4

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

solenoid valve.

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

sis ground.

Connector & terminal

(B137) No. 16 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 V

Repair battery 
short circuit in har-
ness between 
ECM and purge 
control solenoid 
valve connector. 
After repair, 
replace ECM. 
<Ref. to 
FU(H6DO)-46, 
Engine Control 
Module.>

Go to step 5.

5

CHECK PURGE CONTROL SOLENOID 
VALVE.
1) Turn ignition switch to OFF.
2) Measure 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 purge 
control solenoid 
valve <Ref. to 
EC(H6DO)-8, 
Purge Control 
Solenoid Valve.> 
and ECM <Ref. to 
FU(H6DO)-46, 
Engine Control 
Module.>

Go to step 6.

6

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

There is poor contact.

Repair poor con-
tact in ECM con-
nector.

Replace ECM. 
<Ref. to 
FU(H6DO)-46, 
Engine Control 
Module.>