Subaru Legacy IV (2008 year). Service manual — part 365

EN(H4DOTC)(diag)-281

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

23

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Turn the ignition switch to OFF.
2) Measure the resistance between electronic
throttle control relay connector and chassis
ground.

Connector & terminal

(B362) No. 6 — Chassis ground:
(B362) No. 8 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 24.

Repair the ground
short circuit of har-
ness between
ECM and elec-
tronic throttle con-
trol relay.

24

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL RE-
LAY.
Measure the resistance between ECM and
electronic throttle control relay connector.

Connector & terminal

(B136) No. 21 — (B362) No. 6:
(B136) No. 1 — (B362) No. 8:

Is the resistance less than 1

:? Go to step 25.

Repair the open
circuit of harness
between ECM and
electronic throttle
control relay.

25

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
electronic throttle control.
3) Measure the resistance between ECM and
chassis ground.

Connector & terminal

(B134) No. 19 — Chassis ground:
(B134) No. 18 — Chassis ground:
(B134) No. 18 — (B136) No. 6:
(B134) No. 28 — Chassis ground:

Is the resistance 1 M

: or

more?

Go to step 26.

Repair the short
circuit to ground in
harness between
ECM and elec-
tronic throttle con-
trol connector.

26

CHECK SHORT CIRCUIT INSIDE THE ECM.
1) Connect the connector to ECM.
2) Measure the resistance between electronic
throttle control connector and engine ground.

Connector & terminal

(E57) No. 6 — Engine ground:
(E57) No. 4 — Engine ground:

Is the resistance 1 M

: or

more?

Go to step 27.

Repair the short
circuit to ground in
harness between
ECM and elec-
tronic throttle con-
trol connector.
Replace the ECM if
defective. <Ref. to
FU(H4DOTC)-52,
Engine Control
Module (ECM).>

27

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Disconnect the connectors from ECM.
2) Measure the resistance of harness between
ECM and electronic throttle control connector.

Connector & terminal

(B134) No. 18 — (E57) No. 6:
(B134) No. 28 — (E57) No. 4:
(B134) No. 29 — (E57) No. 3:

Is the resistance less than 1

:? Go to step 28.

Repair the open
circuit of harness
between ECM and
electronic throttle
control connector.

Step

Check

Yes

No

EN(H4DOTC)(diag)-282

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

28

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Connect the ECM.
2) Measure the resistance between electronic
throttle control connector and engine ground.

Connector & terminal

(E57) No. 3 — Engine ground:

Is the resistance less than 5

:? Go to step 29.

Repair the harness
and connector.

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

29

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to ON.
2) Measure the voltage between electronic
throttle control connector and engine ground.

Connector & terminal

(E57) No. 6 (+) — Engine ground (–):
(E57) No. 4 (+) — Engine ground (–):

Is the voltage 4.85 V or more?

Repair the short
circuit to power in
the harness
between ECM and
electronic throttle
control connector.

Go to step 30.

30

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between ECM con-
nectors.

Connector & terminal

(B134) No. 19 — (B134) No. 18:
(B134) No. 19 — (B134) No. 28:

Is the resistance 1 M

: or

more?

Go to step 31.

Repair the short
circuit to power in
the harness
between ECM and
electronic throttle
control connector.

31

CHECK SENSOR OUTPUT.
1) Connect all connectors.
2) Turn the ignition switch to ON.
3) Read the data of main throttle sensor signal
using Subaru Select Monitor.

NOTE:
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>

Is the voltage 0.81 — 0.87 V?

Go to step 32.

Repair poor con-
tact of the elec-
tronic throttle
control connector.
Replace the elec-
tronic throttle con-
trol if defective.
<Ref. to
FU(H4DOTC)-14,
Throttle Body.>

32

CHECK SENSOR OUTPUT.
Read the data of sub throttle sensor signal
using Subaru Select Monitor.

NOTE:
Subaru Select Monitor
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H4DOTC)(diag)-34, Subaru Select Moni-
tor.>

Is the voltage 1.64 — 1.70 V?

Go to step 33.

Repair poor con-
tact of the elec-
tronic throttle
control connector.
Replace the elec-
tronic throttle con-
trol if defective.
<Ref. to
FU(H4DOTC)-14,
Throttle Body.>

Step

Check

Yes

No

EN(H4DOTC)(diag)-283

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

33

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM and
electronic throttle control.
3) Measure the resistance between ECM and
electronic throttle control connector.

Connector & terminal

(B137) No. 5 — (E57) No. 2:
(B137) No. 4 — (E57) No. 1:

Is the resistance less than 1

:? Go to step 34.

Repair the harness
and connector.

NOTE:
In this case, repair
the following item:
• Open circuit in
harness between
ECM and electron-
ic throttle control
• Poor contact of
coupling connector

34

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Connect the connector to ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic
throttle control connector and engine ground.

Connector & terminal

(E57) No. 2 (+) — Engine ground (–):
(E57) No. 1 (+) — Engine ground (–):

Is the voltage 5 V or more?

Repair the short
circuit to power in
the harness
between ECM and
electronic throttle
control.

Go to step 35.

35

CHECK HARNESS BETWEEN ECM AND
ELECTRONIC THROTTLE CONTROL MO-
TOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from ECM.
3) Measure the resistance between electronic
throttle control connector and engine ground.

Connector & terminal

(E57) No. 2 — Engine ground:
(E57) No. 1 — Engine ground:

Is the resistance 1 M

: or

more?

Go to step 36.

Repair the short
circuit to ground in
harness between
ECM and elec-
tronic throttle con-
trol.

36

CHECK ELECTRONIC THROTTLE CON-
TROL MOTOR HARNESS.
Measure the resistance between the electronic
throttle control connector terminals.

Connector & terminal

(E57) No. 2 — (E57) No. 1:

Is the resistance 1 M

: or

more?

Go to step 37.

Repair the short
circuit of harness
between ECM and
electronic throttle
control.

37

CHECK ELECTRONIC THROTTLE CON-
TROL GROUND CIRCUIT.
Measure the resistance between ECM and
chassis ground.

Connector & terminal

(B134) No. 5 — Chassis ground:
(B137) No. 1 — Chassis ground:
(B137) No. 2 — Chassis ground:
(B137) No. 3 — Chassis ground:
(B137) No. 7 — Chassis ground:

Is the resistance less than 5

:? Go to step 38.

Repair the open
circuit in harness
between ECM and
engine ground.

38

CHECK ELECTRONIC THROTTLE CON-
TROL.
Measure the resistance between electronic
throttle control terminals.

Terminals

No. 1 — No. 2:

Is the resistance 50

: or less? Go to step 39.

Replace the elec-
tronic throttle con-
trol. <Ref. to
FU(H4DOTC)-14,
Throttle Body.>

39

CHECK ELECTRONIC THROTTLE CON-
TROL.
Move the throttle valve to the fully open and fully
closed positions with fingers.
Check that the valve returns to the specified
position when releasing fingers.

Does the valve return to the
specified position? Standard
value: 3 mm (0.12 in) from fully
closed position

Repair the poor
contact of ECM
connector.

Replace the elec-
tronic throttle con-
trol. <Ref. to
FU(H4DOTC)-14,
Throttle Body.>

Step

Check

Yes

No

EN(H4DOTC)(diag)-284

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

CY:DTC P2004 INTAKE MANIFOLD RUNNER CONTROL STUCK OPEN (BANK 1)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-187, DTC P2004 INTAKE MANIFOLD RUNNER CON-
TROL STUCK OPEN (BANK 1), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
52, OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-43, PRO-
CEDURE, Inspection Mode.>.

CZ:DTC P2005 INTAKE MANIFOLD RUNNER CONTROL STUCK OPEN (BANK 2)

DTC DETECTING CONDITION:
• Immediately at fault recognition
• GENERAL DESCRIPTION <Ref. to GD(H4DOTC)-188, DTC P2005 INTAKE MANIFOLD RUNNER CON-
TROL STUCK OPEN (BANK 2), Diagnostic Trouble Code (DTC) Detecting Criteria.>

CAUTION:
After repair or replacement of faulty parts, perform Clear Memory Mode <Ref. to EN(H4DOTC)(diag)-
52, OPERATION, Clear Memory Mode.>, and Inspection Mode <Ref. to EN(H4DOTC)(diag)-43, PRO-
CEDURE, Inspection Mode.>.

Step

Check

Yes

No

1

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

Check the appro-
priate DTC using
the “List of Diag-
nostic Trouble
Code (DTC)”.
<Ref. to
EN(H4DOTC)(diag)
-81, List of Diag-
nostic 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(H4DOTC)-41,
Tumble Generator
Valve Assembly.>

Step

Check

Yes

No

1

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

Check the appro-
priate DTC using
the “List of Diag-
nostic Trouble
Code (DTC)”.
<Ref. to
EN(H4DOTC)(diag)
-81, List of Diag-
nostic Trouble
Code (DTC).>

Go to step 2.

2

CHECK TUMBLE GENERATOR VALVE LH.
1) Remove the tumble generator valve assem-
bly LH.
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 LH.
<Ref. to
FU(H4DOTC)-41,
Tumble Generator
Valve Assembly.>