Subaru Legacy IV (2008 year). Service manual - part 588

 

  Index      Subaru     Subaru Legacy IV - service and repair manual 2008 year

 

Search            

 

 

 

 

 

 

 

  

 

Content   ..  586  587  588  589   ..

 

 

Subaru Legacy IV (2008 year). Service manual - part 588

 

 

EN(H6DO)(diag)-325

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK ELECTRONIC THROTTLE CON-
TROL RELAY.
1) Turn the ignition switch to OFF.
2) Remove the electronic throttle control relay.
3) Connect the battery to terminals No. 5 and 
No. 6 of electronic throttle control relay.
4) Measure the resistance between electronic 
throttle control relay terminals.

Terminals

No. 7 — No. 8:

Is the resistance less than 1 

:? Go to step 2.

Replace the elec-
tronic throttle con-
trol relay. <Ref. to 
EN(H6DO)(diag)-
8, Electrical Com-
ponent Location.>

2

CHECK POWER SUPPLY OF ELECTRONIC 
THROTTLE CONTROL RELAY.
Measure the voltage between electronic throttle 
control relay connector and chassis ground.

Connector & terminal

(B362) No. 7 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step 3.

Repair the open or 
ground short circuit 
of power supply 
circuit.

3

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL RE-
LAY.
1) Disconnect the connectors from ECM.
2) Turn the ignition switch to ON.
3) Measure the voltage between electronic 
throttle control relay connector and chassis 
ground.

Connector & terminal

(B362) No. 6 (+) — Chassis ground (–):

Is the voltage 10 V or more?

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

Go to step 4.

4

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 5.

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

5

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 6.

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

6

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from 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 7.

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

EN(H6DO)(diag)-326

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

7

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 8.

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(H6DO)-38, 
Engine Control 
Module (ECM).>

8

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 9.

Repair the harness 
and connector.

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

9

CHECK HARNESS BETWEEN ECM AND 
ELECTRONIC THROTTLE CONTROL.
1) Connect the connector to 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 10.

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

10

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 11.

11

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 12.

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

Step

Check

Yes

No

EN(H6DO)(diag)-327

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

12

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(H6DO)(diag)-34, Subaru Select Moni-
tor.>

Is the voltage 0.81 — 0.87 V?

Go to step 13.

Repair poor con-
tact of the elec-
tronic throttle 
control connector. 
Replace the elec-
tronic throttle con-
trol if defective. 
<Ref. to 
FU(H6DO)-13, 
Throttle Body.>

13

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

NOTE:
For detailed operation procedure, refer to
“READ CURRENT DATA FOR ENGINE”. <Ref.
to EN(H6DO)(diag)-34, Subaru Select Moni-
tor.>

Is the voltage 1.64 — 1.70 V?

Go to step 14.

Repair poor con-
tact of the elec-
tronic throttle 
control connector. 
Replace the elec-
tronic throttle con-
trol if defective. 
<Ref. to 
FU(H6DO)-13, 
Throttle Body.>

14

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 15.

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

15

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 16.

16

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 17.

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

17

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 18.

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

Step

Check

Yes

No

EN(H6DO)(diag)-328

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

ENGINE (DIAGNOSTICS)

18

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

Connector & terminal

(B134) No. 3 — Chassis ground:
(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 19.

Repair the harness 
and connector.

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

19

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

Terminals

No. 2 — No. 1:

Is the resistance 50 

: or less? Go to step 20.

Replace the elec-
tronic throttle con-
trol. <Ref. to 
FU(H6DO)-13, 
Throttle Body.>

20

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(H6DO)-13, 
Throttle Body.>

Step

Check

Yes

No

 

 

 

 

 

 

 

Content   ..  586  587  588  589   ..