Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 784

LAN(diag)-45

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

3

CHECK DTC.
1) Turn the ignition switch to OFF.
2) Disconnect all control module connectors
(B280, B310, B136, B230, B231, B380) that are
connected to high speed CAN communication
line.
3) Connect all the disconnected connectors.
4) Turn the ignition switch to ON.
5) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

For models without
SI-DRIVE, Go to
step

5.

For models with SI-
DRIVE, Go to step
4.

Go to step

14.

4

CHECK DCCD CM.
1) Turn the ignition switch to OFF.
2) Disconnect the DCCD CM connector
(B380).
3) Turn the ignition switch to ON.
4) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

Go to step

5.

Go to step

16.

5

CHECK STEERING ANGLE SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the DCCD CM connector.
3) Disconnect the steering angle sensor con-
nector (B231).
4) Turn the ignition switch to ON.
5) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

Go to step

6.

Go to step

17.

6

CHECK YAW RATE SENSOR.
1) Turn the ignition switch to OFF.
2) Connect the steering angle sensor connec-
tor.
3) Disconnect the yaw rate sensor connector
(B230).
4) Turn the ignition switch to ON.
5) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

Go to step

7.

Go to step

18.

7

CHECK VDC/ABS CM.
1) Turn the ignition switch to OFF.
2) Connect the yaw rate sensor connector.
3) Disconnect the VDC/ABS CM connector
(B310).
4) Install the 120 Ω resistance to VDC/ABS
CM connector terminals.

Terminals

(B310) No. 10 — No. 35:

5) Using the tester, measure the resistance
between terminals of data link connector.

Terminals

(B40) No. 6 — No. 14:

Is the resistance 60 Ω?

Go to step

8.

Go to step

10.

8

CHECK DTC.
1) Turn the ignition switch to ON.
2) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

Go to step

9.

Go to step

10.

9

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

Is U1202 a current malfunc-
tion?

Replace the VDC/
ABS CM. <Ref. to
VDC-8,
REMOVAL, VDC
Control Module
and Hydraulic Con-
trol Unit
(VDCCM&H/U).>

Go to step

10.

Step

Check

Yes

No

LAN(diag)-46

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

10

CHECK ECM.
1) Turn the ignition switch to OFF.
2) Connect the VDC/ABS CM.
3) Disconnect the ECM connector (B136).
4) Install the 120 Ω resistance to ECM connec-
tor.

Terminals

(B136) No. 17 — No. 28:

5) Using the tester, measure the resistance
between terminals of data link connector.

Connector & terminal

(B40) No. 6 — No. 14:

Is the resistance 60 Ω?

Go to step

11.

Repair or replace
the open circuit of
harness.

11

CHECK DTC.
1) Turn the ignition switch to ON.
2) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

Go to step

12.

Go to step

13.

12

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

Is U1202 a current malfunc-
tion?

Replace the ECM.
<Ref. to FU(STI)-
59, REMOVAL,
Engine Control
Module (ECM).>
<Ref. to FU(w/o
STI)-57,
REMOVAL, Engine
Control Module
(ECM).>

Go to step

13.

13

CHECK DTC.
1) Turn the ignition switch to OFF.
2) Reconnect all the disconnected connectors.
3) Turn the ignition switch to ON.
4) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

Replace the body
integrated unit.
<Ref. to SL-48,
REMOVAL, Body
Integrated Unit.>

Go to step

14.

14

CHECK HARNESS.
1) Shake the instrument harness and bulk-
head harness, rear harness.
2) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1201 a current malfunc-
tion?

Repair or replace
the harness.

Go to step

15.

15

CHECK CONNECTOR.
1) Disconnect the connector used for CAN cir-
cuit.
2) Check the connector terminal.

Is there poor contact of connec-
tor terminal?

Repair the connec-
tor terminal where
poor contact
exists, or replace
harness.

It is possible that
temporary poor
communication
occurs.

16

CHECK HARNESS.
Using the tester, check the open, short (power
supply-output short, GND-output short) in the
harness between data link connector and
DCCD CM terminals.

Connector & terminal

(B40) No. 14 — (B380) No. 18:
(B40) No. 6 — (B380) No. 2:

Is harness normal?

Replace the DCCD
CM. <Ref. to 6MT-
123, REMOVAL,
Driver’s Control
Center Differential
Control Module.>

Repair or replace
the harness.

17

CHECK HARNESS.
Using the tester, check for open or short (power
supply-output short, GND-output short) in the
harness between terminals of data link connec-
tor and steering angle sensor.

Connector & terminal

(B40) No. 14 — (B231) No. 1:
(B40) No. 6 — (B231) No. 2:

Is harness normal?

Replace the steer-
ing angle sensor.
<Ref. to VDC-22,
REPLACEMENT,
Steering Angle
Sensor.>

Repair or replace
the harness.

Step

Check

Yes

No

LAN(diag)-47

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

18

CHECK HARNESS.
Using the tester, check for open or short (power
supply-output short, GND-output short) in the
harness between terminals of data link connec-
tor and yaw rate sensor.

Connector & terminal

(B40) No. 14 — (B230) No. 3:
(B40) No. 6 — (B230) No. 2:

Is harness normal?

Replace the yaw
rate sensor. <Ref.
to VDC-20,
REMOVAL, Yaw
Rate and G Sen-
sor.>

Repair or replace
the harness.

Step

Check

Yes

No

LAN(diag)-48

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

LAN SYSTEM (DIAGNOSTICS)

G: DTC U1202 CAN-HS BUS OFF

DTC DETECTING CONDITION:

Integrated unit communication is shut down because of high speed CAN error.

TROUBLE SYMPTOM:

Each warning light illuminates because the CAN communication (sending and receiving) is not normal.

WIRING DIAGRAM:

CAN communication system <Ref. to WI-171, WIRING DIAGRAM, CAN Communication System.>

Step

Check

Yes

No

1

CHECK DTC.
Using the Subaru Select Monitor, confirm all
DTCs. <Ref. to LAN(diag)-13, READ DIAG-
NOSTIC TROUBLE CODE (DTC), OPERA-
TION, Subaru Select Monitor.>

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

Perform the diag-
nosis according to
displayed DTC.

Go to step

2.

2

CHECK DTC.
1) Turn the ignition switch to OFF → ON.
2) Read the DTC of body integrated unit using
Subaru Select Monitor.

Is U1202 a current malfunc-
tion?

Go to step

3.

Go to step

10.

2

1

B231

1

8

2

B380

B3

B9

B280

B:

6

14

B40

B380

1 2 3 4

17 18 19 20

5 6 7 8

21 22 23 24

9 10 11 12

25 26 27 28

13 14 15 16
29 30 31 32

4 5 6 7 8 9

6

2

7

2

8

2

9

2

0

3

2 3

1

1

3

2

3

3

3

4

3

5

3

6

3

0

1

1

1

4

1

5

1

6

1

7

1

8

1

9

1

7

3

8

3

9

3

0

4

2

1

3

1

1

4

2

4

3

4

4

4

5

4

6

4

0

2

1

2

3

2

4

2

2

2

5

2

B310

B231

1 2 3 4

B230

1

2

3

4

C: B136

16

10 11 12 13 14 15

25

24

30

9

8

7

17 18 19 20
28

21 22 23

29

32

31

1

2

3

4

5

6

27

26

33 34 35

B280

B:

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

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

B40

C17

C28

C: B136

B230

3

2

B310

10

35

LAN00907

SI

SI

SI

VDC CM

ECM

DCCD CM

YAW RATE &

G SENSOR

: WITH SI-DRIVE

DATA LINK

CONNECTOR

BODY

INTEGRATED

UNIT

STEERING

ANGLE

SENSOR