Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 260

EN(H4DOTC)(diag)-264

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK OUTPUT SIGNAL OF ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM connec-
tor and chassis ground.

Connector & terminal

(B137) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step

2.

Go to step

3.

2

CHECK FOR POOR CONTACT.
Check for poor contact of ECM connector.

Is there poor contact of ECM
connector?

Repair the poor
contact of ECM
connector.

Even if DTC is
detected, the cir-
cuit has returned to
a normal condition
at this time. Repro-
duce the failure,
and then perform
the diagnosis
again.
NOTE:

In this case, tem-
porary open or
short circuit of har-
ness or temporary
poor contact of
connector may be
the cause.

3

CHECK POWER SUPPLY TO PURGE CON-
TROL SOLENOID VALVE CONNECTOR.
Measure the voltage between purge control
solenoid valve connector and engine ground.

Connector & terminal

(E4) No. 1 (+) — Engine ground (–):

Is the voltage 10 V or more?

Go to step

4.

Repair the power
supply circuit.

4

CHECK HARNESS BETWEEN ECM AND
PURGE CONTROL SOLENOID VALVE CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
purge control solenoid valve.
3) Measure the resistance between the purge
control solenoid valve connector and engine
ground.

Connector & terminal

(E4) No. 2 — Engine ground:

Is the resistance 1 MΩ or
more?

Go to step

5.

Repair the short
circuit to ground in
harness between
ECM connector
and purge control
solenoid valve
connector.

5

CHECK HARNESS BETWEEN ECM AND
PURGE CONTROL SOLENOID VALVE CON-
NECTOR.
Measure the resistance of harness between
ECM connector and purge control solenoid
valve connector.

Connector & terminal

(B137) No. 6 — (E4) No. 2:

Is the resistance less than 1 Ω? Go to step

6.

Repair the harness
and connector.
NOTE:

In this case, repair
the following item:
• Open circuit in
harness between
ECM

connector

and purge control
solenoid

valve

connector
• Poor contact of
coupling connector

EN(H4DOTC)(diag)-265

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

6

CHECK PURGE CONTROL SOLENOID
VALVE.
1) Remove the purge control solenoid valve.
2) Measure the resistance between purge con-
trol solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance 10 — 100 Ω? Repair the poor

contact of purge
control solenoid
valve connector.

Replace the purge
control solenoid
valve. <Ref. to
EC(STI)-11, Purge
Control Solenoid
Valve.> <Ref. to
EC(w/o STI)-11,
Purge Control
Solenoid Valve.>

Step

Check

Yes

No

EN(H4DOTC)(diag)-266

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CN:DTC P0459 EVAPORATIVE EMISSION SYSTEM PURGE CONTROL VALVE

CIRCUIT HIGH

DTC DETECTING CONDITION:

• Detected when 2 consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-170, DTC P0459 EVAPORATIVE EMISSION SYS-

TEM PURGE CONTROL VALVE CIRCUIT HIGH, Diagnostic Trouble Code (DTC) Detecting Criteria.>

TROUBLE SYMPTOM:

Improper idling
CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-63,

OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-49, PROCE-

DURE, Inspection Mode.>.

WIRING DIAGRAM:

• Engine electrical system, without SI-DRIVE <Ref. to WI-32, WITHOUT SI-DRIVE, WIRING DIAGRAM,

Engine Electrical System.>

• Engine electrical system, with SI-DRIVE <Ref. to WI-48, WITH SI-DRIVE, WIRING DIAGRAM, Engine

Electrical System.>

ECM

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

29 30 31

32 33

34 35

B135

B:

5

6

7

8

2

1

9

4

3

10

22 23

11 12 13 14 15

24 25

26

16 17

18 19 20 21

27

28 29

30 31

B137

D:

B21

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
42 43

36 37 38 39

48 49 50 51 52 53 54

40 41

44 45

46 47

E52

E4

1 2

B3

D15

D6

E2

B21

44

11

4

8

E4

2

1

E52

2

1

R68

2

1

B135

B:

R57

R15

10

11

R1

B97

R2

B98

7

10

R68

1 2

B220

13
14

15 16

17

27

24

25
26

20

21
22

23

29
30

31

28

32 35

33
34

37
38

39

36

40

8

9

10

11 12

1

2

5

3

4

7

6

19

18

R57

B97

1 2

3 4 5

6 7 8 9 10 11 12

EN-09251

B98

2 3 4 5

6 7 8 9

11 12 13 14

17 18 19 20

1

10

15 16

B220

24

23

22

21

B220

4

3

B137

D:

SBF-7

E

FUSE

(RELAY BLOCK)

MAIN RELAY

BATTERY

PRESSURE CONTROL

SOLENOID VALVE ASSY

PURGE CONTROL

SOLENOID VALVE 2

PURGE CONTROL

SOLENOID VALVE 1

EN(H4DOTC)(diag)-267

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK HARNESS BETWEEN ECM AND
PURGE CONTROL SOLENOID VALVE CON-
NECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
purge control solenoid valve.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM connec-
tor and chassis ground.

Connector & terminal

(B137) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short
circuit to power in
the harness
between ECM con-
nector and purge
control solenoid
valve connector.

Go to step

2.

2

CHECK PURGE CONTROL SOLENOID
VALVE.
1) Turn the ignition switch to OFF.
2) Measure the resistance between purge con-
trol solenoid valve terminals.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 Ω? Replace the purge

control solenoid
valve. <Ref. to
EC(STI)-11, Purge
Control Solenoid
Valve.> <Ref. to
EC(w/o STI)-11,
Purge Control
Solenoid Valve.>

Repair the poor
contact of ECM
connector.