Subaru Legacy IV (2008 year). Service manual - part 1183

LAN(diag)-66

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK DTC.
Connect the Subaru Select Monitor and read all 
DTCs.

Is there any DTC other than for 
the body integrated unit?

Perform the diag-
nosis according to 
the DTC of other 
control modules.

Go to step 2.

2

CHECK DTC.
Check the DTC displayed in the body integrated 
unit.

Is the DTC displayed a current 
malfunction?

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

Go to step 3.

3

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

Is the DTC displayed a current 
malfunction?

Go to step 5.

Go to step 4.

4

CHECK CURRENT DATA.
Using the Subaru Select Monitor, display 
engine speed and vehicle speed signal from 
ECM, TCM, VDC/ABS and body integrated unit 
under the same conditions and compare data.

Do all data values match?

Temporary poor 
contact occurs. 
Perform the Clear 
Memory operation.

Go to step 5.

5

CHECK HARNESS.
1) Disconnect the harness connector of body 
integrated unit.
2) Measure the resistance between harness 
connector terminals.

Connector & terminal

(B280) No. 20 — No. 30:

Is the resistance between 55 — 
65 

:?

Go to step 6.

Open circuit in 
related line of body 
integrated unit. 
Repair the open 
circuit of harness 
or replace har-
ness.

6

CHECK VDC/ABS CM.
1) Connect all connectors.
2) Read the DTC of VDC/ABS CM using the 
Subaru Select Monitor.

Is DTC other than “CAN com-
munication” displayed?

Perform the diag-
nosis according to 
DTC of VDC/ABS 
CM.

Go to step 7.

7

CHECK BODY INTEGRATED UNIT.
1) Connect all the control module connectors.
2) Check the data of “body integrated unit data 
received” on the current data display of ECM 
using Subaru Select Monitor.

Is the “ON” displayed?

Go to step 8.

Replace the body 
integrated unit. 
<Ref. to SL-56, 
REMOVAL, Body 
Integrated Unit.>

8

CHECK BODY INTEGRATED UNIT.
Check the data of “body integrated unit counter 
update” on the data display of ECM.

Is the “ON” displayed?

Replace the VDC/
ABS CM. <Ref. to 
VDC-7, 
REMOVAL, VDC 
Control Module 
and Hydraulic Con-
trol Unit 
(VDCCM&H/U).> 
<Ref. to ABS-6, 
REMOVAL, ABS 
Control Module 
and Hydraulic Con-
trol Unit 
(ABSCM&H/U).>

Replace the body 
integrated unit. 
<Ref. to SL-56, 
REMOVAL, Body 
Integrated Unit.>

LAN(diag)-67

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

P: DTC U1300 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 (except for meters with MID), but communicating function is normal.
WIRING DIAGRAM:

i106

i10

B282

21

22

14

6

i119

A27

A26

B26

B25

i84

B280

10

9

B:

A:

B:

i107

*

1

*

1

*

1

*

1

*

1

*

1

i10

LAN00383

CAN
JOINT
CONNECTOR

ON

WN

WN

ON

TWISTED PAIR LINE

TWISTED PAIR LINE

COMBINATION METER

BODY 

INTEGRATED 

UNIT

i119

1 2 3 4 5 6 7 8
9 10 11 12 13 14 15 16

1 2 3 4 5

6 7 8 9 10

11 12

19 20 21

13 14 15 16 17 18

22

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

21

30

B280

A:

i84

1 2

3 4

5 6

7 8

9 10 11 12

14 15 16 17 18 19 20 21 22 23

24 25

26 27 28 29

30 31 32 33

34 35

13

B282

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 36 37 38 39 40

*

1

ON

WN

WA

WA

WA

AUTO A/C

CONTROL 

MODULE

CENTER

DISPLAY

: TERMINAL No. OPTIONAL ARRANGEMENT

: WITH NAVIGATION

: WITHOUT NAVIGATION 

: WITH AUTO A/C

LAN(diag)-68

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK DTC.
Connect the Subaru Select Monitor and read 
the DTC of the body integrated unit.

Are there any other DTC 
besides U1300?

Perform diagnosis 
according to other 
DTC.

Go to step 2.

2

CHECK DTC.
Check the DTC displayed in the body integrated 
unit.

Is U1300 a current malfunc-
tion?

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

Go to step 3.

3

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

Is U1300 a current malfunc-
tion?

Go to step 4.

Temporary poor 
contact occurs.

4

CHECK CURRENT DATA.
Check the current data (auto A/C failure) of the 
body integrated unit using the Subaru Select 
Monitor.

Is OK displayed?

Go to step 5.

Perform the auto A/
C self-diagnosis. 
<Ref. to AC(diag)-
9, 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 control module 
connector (B282).
3) Connect the Subaru Select Monitor and 
then turn the ignition switch to ON.
4) Perform the clear memory operation for the 
body integrated unit.
5) Read the DTC of the body integrated unit.

Is DTC U1300 detected?

Go to step 6.

Go to step 7.

6

CHECK HARNESS.
1) Disconnect the body integrated unit connec-
tor (B280) and auto A/C control module connec-
tor (B282).
2) Check open or short conditions between 
body integrated unit connector and auto A/C 
control module connector.

Connector & terminal

(B282) No. 10 — (B280) No. 26:
(B282) No. 9 — (B280) No. 25:

Is harness normal?

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

Repair or replace 
the open or short 
circuit of harness.

7

CHECK CURRENT DATA.
Check current data (center display failure) of the 
body integrated unit.

Is OK displayed?

Go to step 8.

Repair or replace 
the center display. 
<Ref. to ET-19, 
REMOVAL, Navi-
gation Display.>

8

CHECK CENTER DISPLAY.
1) Turn the ignition switch to OFF.
2) Disconnect the center display connector 
(i119).
3) Connect the Subaru Select Monitor and 
then turn the ignition switch to ON.
4) Perform the clear memory operation for the 
body integrated unit.
5) Read the DTC of the body integrated unit.

Is DTC U1300 detected?

Go to step 10.

Go to step 9.

9

CHECK HARNESS.
1) Disconnect the body integrated unit connec-
tor (i84) and center display connector (i119).
2) Check open or short conditions between 
body integrated unit connector and center dis-
play connector.

Connector & terminal

(i119) No. 14 — (i84) No. 26:
(i119) No. 6 — (i84) No. 27:

Is harness normal?

Replace the center 
display. <Ref. to 
ET-19, REMOVAL, 
Navigation Dis-
play.>

Repair or replace 
the open or short 
circuit of harness.

LAN(diag)-69

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

10

CHECK CURRENT DATA.
Check current data (meter failure) of the body 
integrated unit.

Is OK displayed?

Go to step 11.

Replace the com-
bination meter. 
<Ref. to IDI-22, 
REMOVAL, Com-
bination Meter.>

11

CHECK COMBINATION METER.
1) Turn the ignition switch to OFF.
2) Disconnect the combination meter connec-
tor (i10).
3) Connect the Subaru Select Monitor and 
then turn the ignition switch to ON.
4) Perform the clear memory operation for the 
body integrated unit.
5) Read the DTC of the body integrated unit.

Is DTC U1300 detected?

Go to step 12.

Go to step 13.

12

CHECK HARNESS.
1) Disconnect the combination meter connec-
tor (i10).
2) Check open or short conditions between 
body integrated unit connector and combination 
meter connector.

Connector & terminal

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

Is harness normal?

Replace the com-
bination meter. 
<Ref. to IDI-22, 
REMOVAL, Com-
bination Meter.>

Repair or replace 
the open or short 
circuit of harness.

13

CHECK HARNESS.
1) Disconnect connectors of A/C ECM (B282), 
center monitor (i119), combination meter (i10) 
and body integrated unit connector (i84).
2) Measure the resistance between connector 
terminals.

Connector & terminal

(i84) No. 27 — (i84) No. 26:

Is the resistance 1 M

: or 

more?

Go to step 14.

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

14

CHECK HARNESS.
1) Connect the disconnected connectors.
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 

:? Repair the short 

circuit of harness 
or replace har-
ness.

Go to step 15.

15

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-56, 
REMOVAL, Body 
Integrated Unit.>

Step

Check

Yes

No