Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 451

6MT(diag)-15

Driver’s Control Center Differential (DCCD) Manual Mode Display

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

B: INSPECTION

DIAGNOSIS:

DCCD manual mode display is open or shorted.

TROUBLE SYMPTOM:

DCCD manual mode display does not illuminate in manual mode.

Step

Check

Yes

No

1

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

Is DTC displayed?

Perform the diag-
nosis according to
DTC.

Go to step

2.

2

CHECK COMBINATION METER.
Perform the self-diagnosis of combination
meter. <Ref. to IDI-5, INSPECTION, Combina-
tion Meter System.>

Is the self-diagnosis of combi-
nation meter OK?

Go to step

3.

Repair it according
to combination
meter diagnostics.

3

CHECK IGNITION POWER SUPPLY CIRCUIT
OF DCCD CONTROL MODULE.
1) Connect the Subaru Select Monitor to the
vehicle.
2) Turn the ignition switch to ON.
3) Read the data of «Battery voltage» using
Subaru Select Monitor.

Is the voltage 11 V or more?

Go to step

4.

Repair the open
circuit of harness
between fuse (F/B
No. 12) and DCCD
control module, or
between fuse (F/B
No. 12) and bat-
tery.

4

CHECK DTC.

Is DTC P1720 displayed?

Perform the diag-
nosis according to
DTC.

Go to step

5.

5

CHECK MODE CHANGE SWITCH.
Read the data of «AUTO/MANUAL Mode
Switch» using the Subaru Select Monitor.

Does the display change to ON/
OFF according to the mode
change switch operation?

Go to step

6.

Diagnose the
mode change
switch.

6

CHECK C.DIFF +/– SWITCH (UP/DOWN).
Read the data of «Up Switch» and «Down
Switch» using the Subaru Select Monitor.

Does the display change to ON/
OFF according to the C.DIFF +/–
switch operation?

Go to step

7.

Check the C.DIFF
+/– switch.

7

CHECK INDICATION OF DCCD MANUAL
MODE DISPLAY.
Press the mode change switch to enter the
manual mode.

Does the DCCD manual mode
display illuminate?

Go to step

8.

Check the poor
contact.

8

CHECK INDICATION OF DCCD MANUAL
MODE DISPLAY.
Read the data of «DCCD Torque Allocation»
using the Subaru Select Monitor.

Does the DCCD manual mode
display change according to the
C.DIFF +/– switch operation?

Go to step

9.

Check the poor
contact.

9

CHECK OTHER DTC.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC.

DCCD manual
mode display is
OK.

6MT(diag)-16

Diagnostic Procedure for Subaru Select Monitor Communication

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

11.Diagnostic Procedure for Subaru Select Monitor Communication

A: COMMUNICATION FOR INITIALIZING IMPOSSIBLE

DIAGNOSIS:

Defective harness connector

TROUBLE SYMPTOM:

Subaru Select Monitor communication failure

WIRING DIAGRAM:

Drivers control center differential control system <Ref. to WI-72, Driver’s Control Center Differential Control

System.>

Step

Check

Yes

No

1

CHECK INSTALLATION OF DCCD CON-
TROL MODULE.
Turn the ignition switch to OFF.

Is the DCCD control module
connector connected to DCCD
control module?

Go to step

2.

Connect the
DCCD control
module connector
to DCCD control
module.

B220

13
14

15 16

17

27

24

25
26

20

21
22

23

29
30

31

28

32 35

33
34

37
38

39

36

40

8

9

10

11 12

1

2

5

3

4

7

6

19

18

B220

26

25

27

2

8

B380

13

14

11

7

2

8

9

2

30

31

17

1

12

4

5

7

6

1

B40

B380

2

1

3 4

6

5

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

MT-02930

B40

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 16

E

SBF-6

E

E

DCCD CM

IGNITION

SWITCH

MAIN SBF

DATA LINK

CONNECTOR

BATTERY

DCCD

RELAY

REF. TO ENGINE ELECTRICAL

SYSTEM

M/B No.

12

F/B No.

12

M/B No. 13

6MT(diag)-17

Diagnostic Procedure for Subaru Select Monitor Communication

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

2

CHECK SUBARU SELECT MONITOR POW-
ER SUPPLY CIRCUIT.
Measure the voltage between data link connec-
tor and chassis ground.

Connector & terminal

(B40) No. 16 (+) — Chassis ground (–):

Is the voltage 10 V or more?

Go to step

3.

Repair harness
connector between
the battery and
data link connec-
tor, and poor con-
tact of the
connector.

3

CHECK SUBARU SELECT MONITOR
GROUND CIRCUIT.
Measure the resistance of harness between
data link connector and chassis ground.

Connector & terminal

(B40) No. 4 — Chassis ground:
(B40) No. 5 — Chassis ground:

Is the resistance less than 1 Ω? Go to step

4.

Repair the open
circuit of harness
between data link
connector and
ground terminal,
and poor contact of
connector.

4

CHECK COMMUNICATION OF SUBARU SE-
LECT MONITOR.
1) Turn the ignition switch to ON.
2) Check communication with the transmission
system.

Is the name of system dis-
played on Subaru Select Moni-
tor?

System is normal. Go to step

5.

5

CHECK COMMUNICATION OF SUBARU SE-
LECT MONITOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from DCCD con-
trol module.
3) Turn the ignition switch to ON.
4) Check communication with the engine sys-
tem.

Is the name of system dis-
played on Subaru Select Moni-
tor?

Go to step

7.

Go to step

6.

6

CHECK COMMUNICATION OF SUBARU SE-
LECT MONITOR.
1) Turn the ignition switch to OFF.
2) Connect the DCCD control module connec-
tor.
3) Disconnect the connector from ECM.
4) Turn the ignition switch to ON.
5) Check communication with the transmission
system.

Is the name of system dis-
played on Subaru Select Moni-
tor?

Inspect the ECM.

Go to step

7.

7

CHECK HARNESS CONNECTOR BETWEEN
EACH CONTROL MODULE AND DATA LINK
CONNECTOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connectors from DCCD con-
trol module and ECM.
3) Measure the resistance between data link
connector and chassis ground.

Connector & terminal

(B40) No. 7 — Chassis ground:

Is the resistance 1 MΩ or
more?

Go to step

8.

Check harness
and connector
between each con-
trol module and
data link connec-
tor.

8

CHECK HARNESS CONNECTOR BETWEEN
EACH CONTROL MODULE AND DATA LINK
CONNECTOR.
1) Disconnect the all modules that communi-
cate with Subaru Select Monitor.
2) Turn the ignition switch to ON.
3) Measure the voltage between data link con-
nector and chassis ground.

Connector & terminal

(B40) No. 7 (+) — Chassis ground (–):

Is the voltage 1 V or more?

Check harness
and connector
between each con-
trol module and
data link connec-
tor.

Go to step

9.

Step

Check

Yes

No

6MT(diag)-18

Diagnostic Procedure for Subaru Select Monitor Communication

MANUAL TRANSMISSION AND DIFFERENTIAL (DIAGNOSTICS)

9

CHECK HARNESS CONNECTOR BETWEEN
DCCD CONTROL MODULE AND DATA LINK
CONNECTOR.
Measure the resistance between DCCD control
module connector and data link connector.

Connector & terminal

(B380) No. 1 — (B40) No. 7:

Is the resistance less than 1 Ω? Go to step

10.

Check harness
and connector
between DCCD
control module and
data link connec-
tor.

10

CHECK POOR CONTACT OF DCCD CON-
TROL MODULE CONNECTOR.

Is there poor contact of connec-
tor?

Repair the poor
contact.

Go to step

11.

11

CHECK POWER SUPPLY OF DCCD CON-
TROL MODULE.
1) Disconnect the connector from DCCD con-
trol module.
2) Turn the ignition switch to ON.
3) Measure the voltage between DCCD con-
trol module connector and chassis ground.

Connector & terminal

(B380) No. 12 (+) — Chassis ground (–):
(B380) No. 13 (+) — Chassis ground (–):
(B380) No. 14 (+) — Chassis ground (–):

Are the voltages 10 — 13 V?

Go to step

15.

Go to step

12.

12

CHECK POWER SUPPLY CIRCUIT OF FUSE
(M/B NO. 12).
1) Turn the ignition switch to OFF.
2) Remove the fuse (M/B No. 12).

Is the fuse (M/B No. 12) blown
out?

Replace the fuse
(M/B No. 12). If the
new fuse (M/B No.
12) has blown out
easily, repair the
short circuit of har-
ness between fuse
(M/B No. 12) and
DCCD control
module.

Go to step

13.

13

CHECK POWER SUPPLY CIRCUIT OF FUSE
(F/B NO. 12).
Remove the fuse (F/B No. 12).

Is the fuse (F/B No. 12) blown
out?

Replace the fuse
(F/B No. 12). If the
new fuse (F/B No.
12) has blown out
easily, repair the
short circuit of har-
ness between fuse
(F/B No. 12) and
DCCD control
module.

Go to step

14.

14

CHECK POWER SUPPLY CIRCUIT OF DCCD
CONTROL MODULE.
Measure the resistance between the battery (+)
terminal and fuse.

Battery & terminal

Battery (+) — M/B No. 12:
Battery (+) — F/B No. 12:

Is the resistance less than 1 Ω? Repair the open

circuit.

Go to step

15.

15

CHECK HARNESS CONNECTOR BETWEEN
DCCD CONTROL MODULE AND CHASSIS
GROUND.
1) Turn the ignition switch to OFF.
2) Measure the resistance between DCCD
control module and chassis ground.

Connector & terminal

(B380) No. 28 — Chassis ground:
(B380) No. 29 — Chassis ground:
(B380) No. 30 — Chassis ground:
(B380) No. 31 — Chassis ground:

Is the resistance less than 1 Ω? Check the poor

contact.

Repair the short
circuit or poor con-
tact of harness
between DCCD
control module and
transmission con-
nector.

Step

Check

Yes

No