Subaru Legacy (2005 year). Service manual — part 136

EN(H4SO 2.0)(diag)-133

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK ANY OTHER DTC ON DISPLAY.

Is any other DTC displayed?

Check DTC using
“List of Diagnostic
Trouble Code
(DTC)”. <Ref. to
EN(H4SO
2.0)(diag)-64, List
of Diagnostic Trou-
ble Code (DTC).>

NOTE:
In this case, it is
not necessary to
inspect DTC
P0301, P0302,
P0303 and P0304.

Go to step 2.

2

CHECK OUTPUT SIGNAL FROM ECM.
1) Turn the ignition switch to ON.
2) Measure the voltage between ECM con-
nector and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 17 (+) — Chassis ground (

−

):

#2 (B134) No. 27 (+) — Chassis ground (

−

):

#3 (B134) No. 34 (+) — Chassis ground (

−

):

#4 (B134) No. 33 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Go to step 7.

Go to step 3.

3

CHECK HARNESS BETWEEN FUEL INJEC-
TOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector
on faulty cylinders.
3) Measure the resistance between ECM con-
nector and engine ground on faulty cylinders.

Connector & terminal

#1 (E5) No. 1 — Engine ground:
#2 (E16) No. 1 — Engine ground:
#3 (E6) No. 1 — Engine ground:
#4 (E17) No. 1 — Engine ground:

Is the resistance more than 1
M

Ω?

Go to step 4.

Repair the ground
short circuit of har-
ness between fuel
injector and ECM
connector.

4

CHECK HARNESS BETWEEN FUEL INJEC-
TOR AND ECM CONNECTOR.
Measure the resistance of harness connector
between ECM connector and fuel injector on
faulty cylinders.

Connector & terminal

#1 (B134) No. 17 — (E5) No. 1:
#2 (B134) No. 27 — (E16) No. 1:
#3 (B134) No. 34 — (E6) No. 1:
#4 (B134) No. 33 — (E17) No. 1:

Is the resistance less than 1
Ω?

Go to step 5.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
ECM and fuel
injector connector
• Poor contact in
coupling connector

5

CHECK FUEL INJECTOR.
Measure the resistance between fuel injector
terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance 5 — 20

Ω?

Go to step 6.

Replace the faulty
fuel injector. <Ref.
to FU(H4SO 2.0)-
29, Fuel Injector.>

EN(H4SO 2.0)(diag)-134

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

6

CHECK POWER SUPPLY LINE.
1) Turn the ignition switch to ON.
2) Measure the voltage between fuel injector
and engine ground on faulty cylinders.

Connector & terminal

#1 (E5) No. 2 (+) — Engine ground (

−

):

#2 (E16) No. 2 (+) — Engine ground (

−

):

#3 (E6) No. 2 (+) — Engine ground (

−

):

#4 (E17) No. 2 (+) — Engine ground (

−

):

Is the voltage more than 10 V? Repair the poor

contact in all con-
nectors in fuel
injector circuit.

Repair the har-
ness and connec-
tor.

NOTE:
In this case, repair
the following item:
• Open circuit of
harness between
main relay and fuel
injector connector
on faulty cylinders
• Poor contact in
coupling connector
• Poor contact in
main relay connec-
tor
• Poor contact in
fuel injector con-
nector on faulty
cylinders

7

CHECK HARNESS BETWEEN FUEL INJEC-
TOR AND ECM CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from fuel injector
on faulty cylinders.
3) Turn the ignition switch to ON.
4) Measure the voltage between ECM con-
nector and chassis ground on faulty cylinders.

Connector & terminal

#1 (B134) No. 17 (+) — Chassis ground (

−

):

#2 (B134) No. 27 (+) — Chassis ground (

−

):

#3 (B134) No. 34 (+) — Chassis ground (

−

):

#4 (B134) No. 33 (+) — Chassis ground (

−

):

Is the voltage more than 10 V? Repair the battery

short circuit of har-
ness between
ECM and fuel
injector. After
repair, replace the
ECM. <Ref. to
FU(H4SO 2.0)-34,
Engine Control
Module (ECM).>

Go to step 8.

8

CHECK FUEL INJECTOR.
1) Turn the ignition switch to OFF.
2) Measure the resistance between fuel injec-
tor terminals on faulty cylinder.

Terminals

No. 1 — No. 2:

Is the resistance less than 1
Ω?

Replace the faulty
fuel injector<Ref.
to FU(H4SO 2.0)-
29, Fuel Injector.>
and ECM <Ref. to
FU(H4SO 2.0)-34,
Engine Control
Module (ECM).>.

Go to step 9.

9

CHECK INSTALLATION OF CAMSHAFT PO-
SITION SENSOR/CRANKSHAFT POSITION
SENSOR.

Is the camshaft position sensor
or crankshaft position sensor
loosely installed?

Tighten the cam-
shaft position sen-
sor or crankshaft
position sensor.

Go to step 10.

10

CHECK CRANK SPROCKET.
Remove the timing belt cover.

Is the crank sprocket rusted or
does it have broken teeth?

Replace the crank
sprocket. <Ref. to
ME(H4SO 2.0)-50,
Crank Sprocket.>

Go to step 11.

11

CHECK INSTALLATION CONDITION OF
TIMING BELT.
Turn the crankshaft using ST, and align align-
ment mark on crank sprocket with alignment
mark on cylinder block.
ST

499987500

CRANKSHAFT SOCKET

Is the timing belt dislocated
from its proper position?

Correct the instal-
lation condition of
timing belt. <Ref.
to ME(H4SO 2.0)-
43, Timing Belt.>

Go to step 12.

Step

Check

Yes

No

EN(H4SO 2.0)(diag)-135

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

12

CHECK FUEL LEVEL.

Is the fuel gauge indication
higher than the “Lower” level?

Go to step 13.

Replenish fuel so
fuel gauge indica-
tion is higher than
the “Lower” level.
After replenishing
fuel, Go to step 13.

13

CHECK STATUS OF MALFUNCTION INDI-
CATOR LIGHT.
1) Perform the clear memory mode using
Subaru Select Monitor.
<Ref. to EN(H4SO 2.0)(diag)-38, Clear Mem-
ory Mode.>
2) Start the engine, and drive the vehicle more
than 10 minutes.

Does the malfunction indicator
light illuminate or blink?

Go to step 15.

Go to step 14.

14

CHECK CAUSE OF MISFIRE DIAGNOSED.

Has the cause of misfire been
detected while running the
engine? Ex. Disconnection of
spark plug cord.

Finish diagnostics
operation, if the
engine has no
abnormality.

1. Repair the poor
contact.

NOTE:
In this case, repair
the following item:
• Poor contact in
ignitor connector
• Poor contact in
ignition coil con-
nector
• Poor contact in
fuel injector con-
nector on faulty
cylinders
• Poor contact in
ECM connector
• Poor contact in
coupling connector

2. If there is no
poor contact,
check the follow-
ings and contact
the SUBARU
dealer.

• Fuel condi-
tion
• Whether
additive is used
or not
• Plug condi-
tion
• Plug cord
condition
• Engine oil
condition

Step

Check

Yes

No

EN(H4SO 2.0)(diag)-136

ENGINE (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

15

CHECK AIR INTAKE SYSTEM.

Is there any fault in air intake
system?

Repair the air
intake system.

NOTE:
Check the follow-
ing items.
• Are there air
leaks or air suction
caused by loose or
dislocated nuts
and bolts?
• Are there cracks
or any disconnec-
tion of hoses?

Go to step 16.

16

CHECK MISFIRE SYMPTOM.
1) Turn the ignition switch to ON.
2) Read the DTC.
• Subaru Select Monitor
<Ref. to EN(H4SO 2.0)(diag)-25, Subaru
Select Monitor.>
• General scan tool
For detailed operation procedure, refer to the
general scan tool operation manual.

NOTE:

Perform diagnosis according to the items listed
below.

Does the Subaru Select Moni-
tor or general scan tool display
only one DTC?

Go to step 21.

Go to step 17.

17

CHECK ANY OTHER DTC ON DISPLAY.

Are DTC P0301 and P0302
displayed?

Go to step 22.

Go to step 18.

18

CHECK DTC ON DISPLAY.

Are DTC P0303 and P0304
displayed?

Go to step 23.

Go to step 19.

19

CHECK DTC ON DISPLAY.

Are DTC P0301 and P0303
displayed?

Go to step 24.

Go to step 20.

20

CHECK DTC ON DISPLAY.

Are DTC P0302 and P0304
displayed?

Go to step 25.

Go to step 26.

21

ONLY ONE CYLINDER

Is there any fault in the cylin-
der?

Repair or replace
faulty parts.

NOTE:
Check the follow-
ing items.
• Spark plug
• Spark plug cord
• Fuel injector
• Compression
ratio

Go to DTC P0171.
<Ref. to EN(H4SO
2.0)(diag)-123,
DTC P0171 SYS-
TEM TOO LEAN
(BANK 1), Diag-
nostic Procedure
with Diagnostic
Trouble Code
(DTC).>

Step

Check

Yes

No