Subaru Legacy III (2000-2003 year). Manual - part 147

EN(H4SO)-200

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

AP: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(H4SO)-47, OPER-
ATION, Clear Memory Mode.> and Inspection Mode <Ref. to EN(H4SO)-40, OPERATION, Inspection 
Mode.> .
• WIRING DIAGRAM:

EN-01131

F44

B61

6

RHD

RHD

PURGE CONTROL

SOLENOID VALVE

E4

B22

E3

B47

B47

3

4

1

2

5

6

B134

1 2

3 4

5 6

7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

24 25

26 27 28 29

30 31 32 33

34 35

B22

1 2 3 4
5 6 7 8
9 10 11 12

13 14 15 16

SBF-5

BATTERY

MAIN RELAY

1

2

3

5

4

6

29

2

1

1

2

B134

ECM

F44

1 2 3 4
5 6 7 8

E4

1 2

LHD

LHD

EN(H4SO)-201

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 at the lower 

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

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(H4SO)-48, Compul-
sory Valve Operation Check Mode.>  

Connector & terminal

(B134) No. 29 (+) — Chassis ground (

−−−−

):

Does the measured value exceed the spec-
ified value?

10 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 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

(B134) No. 29 (+) — 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 poor con-
tact in ECM con-
nector.

Replace ECM.  
<Ref. to 
FU(H4SO)-45, 
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

(B134) No. 29 (+) — 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(H4SO)-45, 
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(H4SO)-7, 
Purge Control 
Solenoid Valve.> 
and ECM  <Ref. to 
FU(H4SO)-45, 
Engine Control 
Module.>

Go to step 6.

EN(H4SO)-202

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

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(H4SO)-45, 
Engine Control 
Module.>

Step

Value

Yes

No

EN(H4SO)-203

ENGINE (DIAGNOSTICS)

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)

MEMO: