Subaru Legacy (2005 year). Manual - part 1047

LAN(diag)-67

LAN SYSTEM (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

R: DTC B0300 CAN-LS MALFUNCTION

DTC DETECTING CONDITION:
Either end of low-speed CAN communication line is open or shorted, the connector is not connected prop-
erly, or the terminal has poor crimping.
TROUBLE SYMPTOM:
“Er LC” is displayed in odo/trip meter, but communicating function is OK.
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK DTC.
Read the DTC of body integrated unit using 
Subaru Select Monitor. 

Is there any DTC other than 
B0300?

Perform the diag-
nosis according to 
other DTC.

Go to step 2.

2

CHECK DTC.
Check the DTC displayed in the body inte-
grated unit.

Is the DTC displayed currently 
malfunctioning?

Check the connec-
tion of harness 
connector. Go to 
step 3.

Go to step 3.

3

CHECK DTC.
Turn the ignition switch to OFF and read the 
DTC again.

Is B0300 currently malfunction-
ing?

Go to step 4.

Temporary poor 
contact occurs.

i77

 i10

B283

21

22

14

6

i90

A27

A26

B26

B25

A:     i84

B:   B280

1

11

:

AE

AE

AE

4

2

  i92

5

4

6 7

8

2

1

9

3

10

22

23

11 12 13 14 15

24 25

26 27

16 17 18

28 29

19 20

0

3

1

2

B:   B280

A:    i84

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

i90

2 3 4 5

6 7 8 9

12 13 14 15 16 17 18 19 20 21 22

10

1

11

5 6 7

8

2

1

4

3

11

10

12 13 14 15

8

16

B283

9

19 20

10

5 6 7

2

1

4

3

13

12

11

14 15 16 17

8

18

i10

i77

1 2 3 4 5 6 7 8 9 10 11 12

i92

1 2
3 4

WN

:

ON

:

:

:

1

*

2

*

WN

ON

WN

ON

1

*

2

*

1

*

1

*

2

*

2

*

CAN JOINT  
CONNECTOR
 

LAN00254

COMBINATION METER

TWISTED P

AIR LINE

BODY 
INTEGRATED 
UNIT

CENTER 
DISPLAY

CENTER 
DISPLAY

AUTO A/C 
CONTROL 
MODULE

WITHOUT NAVIGATION

WITH NAVIGATION

TERMINAL No. OPTIONAL 
ARRANGEMENT 
AMONG 1, 2, 3, 4, 5 AND 6

TERMINAL No. OPTIONAL 
ARRANGEMENT  
AMONG 7, 8, 9, 10, 11 AND 12

WITH AUTO A/C

LAN(diag)-68

LAN SYSTEM (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

4

CHECK CURRENT DATA.
Connect the Subaru Select Monitor and dis-
play current data of the body integrated unit 
(auto A/C fail).

Is OK displayed?

Go to step 5.

Perform auto A/C 
self-diagnosis. 
<Ref. to AC(diag)-
10, OPERATION, 
Diagnostic Chart 
for Self-Diagno-
sis.>

5

CHECK AUTO A/C ECM.
1) Turn the ignition switch to OFF.
2) Disconnect the auto A/C ECM connector 
(B283).
3) Turn the ignition switch to ON and read the 
DTC.

Does B0300 disappear?

Go to step 6.

Go to step 7.

6

CHECK HARNESS.
1) Disconnect the body integrated unit con-
nector (B280) and auto A/C control module 
connector (B283).
2) Check for open and short circuits between 
body integrated unit connector and auto A/C 
control module connector.

Connector & terminal

(B283) No. 1 — (B280) No. 26:
(B283) No. 11 — (B280) No. 25:

Is the harness in normal condi-
tion?

Replace the auto 
A/C ECM. <Ref. to 
AC-33, REMOVAL, 
Control Unit (Auto 
A/C Model).>

Repair or replace 
the open or short 
circuit of harness.

7

CHECK CURRENT DATA.
Connect the Subaru Select Monitor and dis-
play current data of the body integrated unit 
(meter fail).

Is OK displayed?

Go to step 8.

Replace the com-
bination meter. 
<Ref. to IDI-15, 
REMOVAL, Com-
bination Meter.>

8

CHECK COMBINATION METER.
1) Turn the ignition switch to OFF.
2) Disconnect the combination meter connec-
tor.
3) Turn the ignition switch to ON.

Is B0300 detected?

Go to step 10.

Go to step 9.

9

CHECK HARNESS.
1) Disconnect the combination meter connec-
tor (i10).
2) Check for open and short circuits between 
the body integrated unit and combination 
meter connectors.

Connector & terminal

(i10) No. 21 — (i84) No. 27:
(i10) No. 22 — (i84) No. 26:

Is the harness in normal condi-
tion?

Replace the com-
bination meter. 
<Ref. to IDI-15, 
REMOVAL, Com-
bination Meter.>

Repair or replace 
the open or short 
circuit of harness.

10

CHECK HARNESS.
1) Disconnect the CAN junction connector 
(i77) and the body integrated unit connector 
(i84).
2) Measure the resistance between connector 
terminals.

Connector & terminal

(i84) No. 27 — (i77) No. 1 — 6:
(i84) No. 26 — (i77) No. 7 — 12:

NOTE:

The junction connector of i77 is in user defined
alignment.

Is the resistance less than 
10

Ω?

Go to step 11.

Repair the short 
circuit of harness 
or replace har-
ness.

Step

Check

Yes

No

LAN(diag)-69

LAN SYSTEM (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

11

CHECK HARNESS.
1) Disconnect the combination meter connec-
tor.
2) Measure the resistance between the junc-
tion connector and the combination meter con-
nector.

Connector & terminal

(i10) No. 21 — (i77) No. 1 — 6:
(i10) No. 22 — (i77) No. 7 — 12:

NOTE:

The junction connector of i77 are in user de-
fined alignment.

Is the resistance less than 
10

Ω?

Go to step 12.

Repair the open 
circuit of harness 
or replace har-
ness.

12

CHECK HARNESS.
1) Disconnect the body integrated unit con-
nector (B280) and auto A/C control module 
connector (B283).
2) Measure the resistance between body inte-
grated unit connector and auto A/C control 
module connector.

Connector & terminal

(B283) No. 1 — (B280) No. 26:
(B283) No. 11 — (B280) No. 25:

Is the resistance less than 
10

Ω?

Go to step 13.

Repair the open 
circuit of harness 
or replace har-
ness.

13

CHECK HARNESS.
1) Connect the junction connector.
2) Measure the resistance between body inte-
grated unit connector and chassis ground.

Connector & terminal

(B280) No. 25 — Chassis ground:
(B280) No. 26 — Chassis ground:
(i84) No. 26 — Chassis ground:
(i84) No. 27 — Chassis ground:

Is the resistance less than 
10

Ω?

Repair the short 
circuit of harness 
or replace har-
ness.

Go to step 14.

14

CHECK HARNESS.
1) Turn the ignition switch to ON.
2) Measure the voltage between body inte-
grated unit connector and chassis ground.

Connector & terminal

(B280) No. 25 (+) — Chassis ground(

−

):

(B280) No. 26 (+) — Chassis ground(

−

):

(i84) No. 26 (+) — Chassis ground(

−

):

(i84) No. 27 (+) — Chassis ground(

−

):

Is the voltage 6 V or more?

Repair the short 
circuit of harness 
or replace har-
ness.

Replace the body 
integrated unit. 
<Ref. to SL-44, 
REMOVAL, Body 
Integrated Mod-
ule.>

Step

Check

Yes

No

LAN(diag)-70

LAN SYSTEM (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

S: DTC B0301 CAN-LS COUNTER ABNORMAL

DTC DETECTING CONDITION:
Find the unit in which trouble occurs and open or short CAN line, and repair and replace them.
(Free running counter error may be detected at the same time from the unit in which the malfunction occurs.)
TROUBLE SYMPTOM:
“Er LC” is displayed in odo/trip meter.
WIRNG DIAGRAM:

Step

Check

Yes

No

1

CHECK DTC.
Read the DTC of body integrated unit using 
Subaru Select Monitor.

Is there any DTC other than 
B0301?

Perform the diag-
nosis according to 
other DTC.

Go to step 2.

2

CHECK DTC.
Check the DTC displayed in the body inte-
grated unit.

Is the DTC displayed currently 
malfunctioning?

Check the connec-
tion of harness 
connector. Go to 
step 3.

Go to step 3.

3

CHECK DTC.
Turn the ignition switch to OFF and read the 
DTC again.

Is B0301 currently malfunction-
ing?

Go to step 4.

Temporary poor 
contact occurs.

i77

 i10

B283

21

22

14

6

i90

A27

A26

B26

B25

A:     i84

B:   B280

1

11

:

AE

AE

AE

4

2

  i92

5

4

6 7

8

2

1

9

3

10

22

23

11 12 13 14 15

24 25

26 27

16 17 18

28 29

19 20

0

3

1

2

B:   B280

A:    i84

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

i90

2 3 4 5

6 7 8 9

12 13 14 15 16 17 18 19 20 21 22

10

1

11

5 6 7

8

2

1

4

3

11

10

12 13 14 15

8

16

B283

9

19 20

10

5 6 7

2

1

4

3

13

12

11

14 15 16 17

8

18

i10

i77

1 2 3 4 5 6 7 8 9 10 11 12

i92

1 2
3 4

WN

:

ON

:

:

:

1

*

2

*

WN

ON

WN

ON

1

*

2

*

1

*

1

*

2

*

2

*

CAN JOINT  
CONNECTOR
 

LAN00254

COMBINATION METER

TWISTED P

AIR LINE

BODY 
INTEGRATED 
UNIT

CENTER 
DISPLAY

CENTER 
DISPLAY

AUTO A/C 
CONTROL 
MODULE

WITHOUT NAVIGATION

WITH NAVIGATION

TERMINAL No. OPTIONAL 
ARRANGEMENT 
AMONG 1, 2, 3, 4, 5 AND 6

TERMINAL No. OPTIONAL 
ARRANGEMENT  
AMONG 7, 8, 9, 10, 11 AND 12

WITH AUTO A/C