Subaru Legacy III (2000-2003 year). Service 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: