Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 271

EN(H4DOTC)(diag)-308

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

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

Connector & terminal

(B135) No. 3 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Repair the short
circuit to power in
harness between
ECM connector
and pressure con-
trol solenoid valve
assembly connec-
tor.

Go to step

2.

2

CHECK PRESSURE CONTROL SOLENOID
VALVE ASSEMBLY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between terminals
of pressure control solenoid valve assembly.

Terminals

No. 1 — No. 2:

Is the resistance less than 1 Ω? Replace the pres-

sure control sole-
noid valve
assembly. <Ref. to
EC(STI)-16, Pres-
sure Control Sole-
noid Valve
Assembly.> <Ref.
to EC(w/o STI)-17,
Pressure Control
Solenoid Valve
Assembly.>

Repair the poor
contact of ECM
connector.

EN(H4DOTC)(diag)-309

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DO:DTC P1449 EVAPORATIVE EMISSION CONT. SYS. AIR FILTER CLOG

DTC DETECTING CONDITION:

• Detected when 2 consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-213, DTC P1449 EVAPORATIVE EMISSION CONT.

SYS. AIR FILTER CLOG, Diagnostic Trouble Code (DTC) Detecting Criteria.>
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.>.

Step

Check

Yes

No

1

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check the appropri-
ate DTC using the
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
EN(H4DOTC)(diag)
-87, List of Diagnos-
tic Trouble Code
(DTC).>

Go to step

2.

2

CHECK DRAIN TUBE CONNECTED TO
LEAK CHECK VALVE ASSEMBLY.

Is the drain tube A or the drain
tube B connected to the leak
check valve assembly
clogged?

Replace the drain
tube A or the drain
tube B connected
to the leak check
valve assembly.
<Ref. to EC(STI)-
19, Leak Check
Valve Assembly.>
<Ref. to EC(w/o
STI)-20, Leak
Check Valve
Assembly.>

Go to step

3.

3

CHECK DRAIN HOSE AND HOSE CONNEC-
TOR BETWEEN LEAK CHECK VALVE AS-
SEMBLY AND DRAIN SEPARATOR.

Is the drain hose or the hose
connector between leak check
valve assembly and drain sepa-
rator clogged?

Replace the drain
hose or the hose
connector between
leak check valve
assembly and
drain separator.
<Ref. to EC(STI)-
7, Canister.> <Ref.
to EC(w/o STI)-7,
Canister.> <Ref. to
EC(STI)-23, Drain
Separator.> <Ref.
to EC(w/o STI)-24,
Drain Separator.>

Go to step

4.

4

CHECK DRAIN SEPARATOR.

Is the drain separator clogged? Replace the drain

separator. <Ref. to
EC(STI)-23, Drain
Separator.> <Ref.
to EC(w/o STI)-24,
Drain Separator.>

Replace the leak
check valve
assembly. <Ref. to
EC(STI)-19, Leak
Check Valve
Assembly.> <Ref.
to EC(w/o STI)-20,
Leak Check Valve
Assembly.>

EN(H4DOTC)(diag)-310

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DP:DTC P1451 EVAPORATIVE EMISSION CONT. SYS.

DTC DETECTING CONDITION:

• Detected when two consecutive driving cycles with fault occur.

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-215, DTC P1451 EVAPORATIVE EMISSION CONT.

SYS., Diagnostic Trouble Code (DTC) Detecting Criteria.>
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.>.

Step

Check

Yes

No

1

CHECK DRAIN TUBE BETWEEN CANISTER
AND LEAK CHECK VALVE ASSEMBLY.

Is the drain tube between can-
ister and leak check valve
assembly clogged?

Replace the drain
tube between the
canister and leak
check valve
assembly. <Ref. to
EC(STI)-7, Canis-
ter.> <Ref. to
EC(w/o STI)-7,
Canister.>

Go to step

2.

2

CHECK HOSES BETWEEN CANISTER AND
FUEL TANK.

Are the hoses between the can-
ister and fuel tank clogged?

Replace the hoses
between the canis-
ter and fuel tank.
<Ref. to EC(STI)-
7, Canister.> <Ref.
to EC(w/o STI)-7,
Canister.> <Ref. to
FU(STI)-70, Fuel
Tank.> <Ref. to
FU(w/o STI)-68,
Fuel Tank.>

Replace the canis-
ter. <Ref. to
EC(STI)-7, Canis-
ter.> <Ref. to
EC(w/o STI)-7,
Canister.>
After the operation
is complete, go to
the next step. Go
to step

3.

3

CHECK EVAPORATIVE EMISSION CON-
TROL SYSTEM.
Perform drive cycle I. <Ref. to
EN(H4DOTC)(diag)-59, DRIVE CYCLE H,
PROCEDURE, Drive Cycle.>

Is DTC P1451 displayed on the
display?

Replace the leak
check valve
assembly. <Ref. to
EC(STI)-19, Leak
Check Valve
Assembly.> <Ref.
to EC(w/o STI)-20,
Leak Check Valve
Assembly.>

End.

EN(H4DOTC)(diag)-311

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

DQ:DTC P2004 INTAKE MANIFOLD RUNNER CONTROL STUCK OPEN

(BANK 1)

DTC DETECTING CONDITION:

• Immediately at fault recognition

• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-216, DTC P2004 INTAKE MANIFOLD RUNNER CON-

TROL STUCK OPEN (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>
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.>.

Step

Check

Yes

No

1

CHECK FOR ANY OTHER DTC ON DISPLAY. Is any other DTC displayed?

Check the appropri-
ate DTC using the
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
EN(H4DOTC)(diag)
-87, List of Diagnos-
tic Trouble Code
(DTC).>

Go to step

2.

2

CHECK TUMBLE GENERATOR VALVE RH.
1) Remove the tumble generator valve assem-
bly RH.
2) Check the tumble generator valve body.

Is there any dirt or clogging with
foreign objects in the tumble
generator valve?

Clean the tumble
generator valve.

Replace the tum-
ble generator valve
assembly RH.
<Ref. to FU(STI)-
48, Tumble Gener-
ator Valve Assem-
bly.> <Ref. to
FU(w/o STI)-48,
Tumble Generator
Valve Assembly.>