Subaru Legacy IV (2008 year). Manual — part 939

VDC(diag)-71

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

AI: DTC C0054 BLS ON MALFUNCTION

DTC DETECTING CONDITION:
Defective stop light switch
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

1 2
3 4

9

4

7

6

2

1
5

3
8

B65

B159

B310

30

VDCCM & H/U

59

B159

B225

B65

3

2

E

MAIN SBF

SBF-2

No.8

7.5A

3

4

B310

4 5 6 7 8 9

26 27 28 29 30

2 3

1

31 32 33 34 35 36

10 11

14 15 16 17 18 19

37 38 39 40

12 13

41 42 43 44 45 46

20 21

23

24

22

25

VDC00502

B225

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

BATTERY

STOP LIGHT
SWITCH

FUSE
(RELAY BLOCK)

VDC(diag)-72

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the stop light switch connector.
3) Measure the resistance of stop light switch
terminals.

Is the resistance 1 M

: or more

when switch is OFF (when
pedal is not depressed)?

Go to step 2.

Replace the stop
light switch.

2

INTERVIEWING CUSTOMERS.
Make sure that the operation was performed in
which accelerator pedal and brake pedal were
depressed simultaneously (with depressing
brake pedal with left foot).

Were the acceleration pedal
and brake pedal depressed
simultaneously?

System is normal.
(DTC may be
recorded while
brake is applied
during driving.)

Go to step 3.

3

CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-23,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-22, Inspection Mode.>
4) Read the DTC.

Is the same DTC displayed?

Replace the
VDCCM only.
<Ref. to VDC-10,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Go to step 4.

4

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-34, List
of Diagnostic Trou-
ble Code (DTC).>

Temporary poor
contact occurs.

VDC(diag)-73

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

AJ:DTC C0054 BLS OFF MALFUNCTION

DTC DETECTING CONDITION:
Defective stop light switch
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

1 2
3 4

9

4

7

6

2

1
5

3
8

B65

B159

B310

30

VDCCM & H/U

59

B159

B225

B65

3

2

E

MAIN SBF

SBF-2

No.8

7.5A

3

4

B310

4 5 6 7 8 9

26 27 28 29 30

2 3

1

31 32 33 34 35 36

10 11

14 15 16 17 18 19

37 38 39 40

12 13

41 42 43 44 45 46

20 21

23

24

22

25

VDC00502

B225

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

BATTERY

STOP LIGHT
SWITCH

FUSE
(RELAY BLOCK)

VDC(diag)-74

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK STOP LIGHT SWITCH.
1) Turn the ignition switch to OFF.
2) Disconnect the stop light switch connector.
3) Measure the resistance of stop light switch
terminals.

Is the resistance 0.5

: or less

when the switch is ON (when
pedal is depressed)?

Go to step 2.

Replace the stop
light switch.

2

CHECK POWER SUPPLY OF STOP LIGHT
SWITCH.
Measure the voltage between the stop light
switch terminal and chassis ground.

Connector & terminal

(B65) No. 2 (+) — Chassis ground (–):

Is the voltage 10 — 15 V?

Go to step 3.

Repair the power
supply circuit of
stop light.

3

CHECK STOP LIGHT SWITCH HARNESS.
1) Disconnect the connector from the
VDCCM&H/U.
2) Measure the resistance between
VDCCM&H/U and stop light switch.

Connector & terminal

(B65) No. 3 — (B310) No. 30:

Is the resistance less than 0.5

:? Go to step 4.

Repair the stop
light switch circuit.

4

CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in connec-

tor between stop light switch
and VDCCM&H/U?

Repair the connec-
tor.

Go to step 5.

5

CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-23,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-22, Inspection Mode.>
4) Read the DTC.

Is the same DTC displayed?

Replace the
VDCCM only.
<Ref. to VDC-10,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Go to step 6.

6

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-34, List
of Diagnostic Trou-
ble Code (DTC).>

Temporary poor
contact occurs.