Subaru Legacy III (2000-2003 year). Manual - part 791

VDC-200

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

AJ:DTC 49 ABNORMAL ENGINE SPEED SIGNAL

DIAGNOSIS:
• Engine speed signal line is broken or short circuited.
TROUBLE SYMPTOM:
• VDC does not operate.
WIRING DIAGRAM:

VDC00180

C9

A30

9

VDC

CONTROL

MODULE

F87

F87

56 57

59 60

62 63

65

82 83

80

27

28

25

26

23

24

21

22

19

20

17

18

15

16

13

14

11

12

9

10

7

8

5

6

3

4

1

2

54

55

52

53

50

51

81

48

49

46

47

44

45

78

79

76

77

75

42

43

40

41

74

72

73

70

71

39

37

38

35

36

69

67

68

66

33

34

61

64

31

32

29

30

58

1 2

7

8 9

5

6

3

4

10 11 12
19 20 21

13 14 15 16

17 18

22 23 24

H6

RH4

A10

A10

WO

O

O

LH4

ENGINE

CONTROL

MODULE

B134

B136

A:

:

C:

:

H4

H6

B136

C:

: H6

B134

A:

: H4

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

: 4 CYLINDER ENGINE RHD MODEL

: 4 CYLINDER ENGINE LHD MODEL

RH4

LH4

: 4 CYLINDER ENGINE

: 6 CYLINDER ENGINE

H4

H6

: RHD MODEL

: LHD MODEL

R

L

: WITHOUT OBD MODEL

: WITH OBD MODEL

OO

WO

1 2 3

4 5 6

7 8 9 10 11 12 13 14

F96

L

:

F96

R

:

1 2 3 4

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20

10

R

3

L

F96

B255

VDC-201

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

Step

Value

Yes

No

1

CHECK TACHOMETER OPERATION IN 
COMBINATION METER.
Does tachometer operate normally?

Operates properly.

Go to step 2.

Repair tachome-
ter.

2

CHECK HARNESS BETWEEN VDCCM AND 
ECM.
1) Turn ignition switch to OFF.
2) Disconnect connector from VDCCM and 

ECM.

3) Measure resistance between VDCCM con-

nector and ECM.

Connector & terminal

H4 engine RHD without OBD model

(F87) No. 9 — (B134) No. 10:

H4 engine RHD with OBD model

(F87) No. 9 — (B134) No. 30:

H4 engine LHD model

(F87) No. 9 — (B134) No. 10:

H6 engine model

(F87) No. 9 — (B136) No. 9:

Is the measured value less than the speci-
fied value?

0.5 

Ω

Go to step 3.

Repair harness 
connector 
between VDCCM 
and ECM.

3

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connectors between 
VDCCM and ECM?

There is poor contact.

Repair connector.

Go to step 4.

4

CHECK VDCCM.
1) Connect all connectors.
2) Erase the memory.
3) Perform inspection mode.
4) Read out the diagnostic trouble code.

Is the same diagnostic trouble code as in 
the current diagnosis still being output?

Same DTC indicated.

Replace VDCCM.  
<Ref. to VDC-8, 
VDC Control Mod-
ule (VDCCM).>

Go to step 5.

5

CHECK ANY OTHER DIAGNOSTIC TROU-
BLE CODES APPEARANCE.
Are other diagnostic trouble codes being out-
put?

Other DTC indicated.

Proceed with the 
diagnosis corre-
sponding to the 
diagnostic trouble 
code.

A temporary poor 
contact.

VDC-202

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

AK:DTC 51 VALVE RELAY

DIAGNOSIS:
• Faulty valve relay

NOTE:
When DTC 74 inspection is carried out, DTC 51 is memorized.
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

VDC00150

10

9

11

12

15

13

16

14

VDC HYDRAULIC UNIT

VALVE RELAY

87

87a

VDC2

VDC1

4

6

86

1

85

30

30

86

85

87

5

VDC4

F90

VDC5

F91

F87

56 57

59 60

62 63

65

82 83

80

27

28

25

26

23

24

21

22

19

20

17

18

15

16

13

14

11

12

9

10

7

8

5

6

3

4

1

2

54

55

52

53

50

51

81

48

49

46

47

44

45

78

79

76

77

75

42

43

40

41

74

72

73

70

71

39

37

38

35

36

69

67

68

66

33

34

61

64

31

32

29

30

58

SBF-3 50A

VDC7

VDC6

MOTOR RELAY

VALVE RELAY

VDC CONTROL MODULE

22

10

27

47

F87

1
2

F89

VDC3

1

SBF-1 100A

RELAY BOX

F89

VDC1

1 2

F90

1

3

4 5 6

2

NO. 8 30A 

FR OUTLET

FR INLET

RL OUTLET

RL INLET

RR OUTLET

RR INLET

PRIMAR

Y CUT

PRIMAR

Y SECTION

SECOND

AR

Y CUT

PRIMAR

Y

PRESSURE SENSOR

SECOND

A

R

Y

PRESSURE SENSOR

SECOND

AR

Y SECTION

FL OUTLET

FL INLET

51

30

3

31

4

23

50

24

25

2

26

36

76

77

78

29

4

5

1

6

2

7

3

8

85

86

87

87a

30

85

86

87

30

F91

VDC6

VDC7

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

BATTERY

VDC-203

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

Step

Value

Yes

No

1

CHECK RESISTANCE OF VALVE RELAY.
1) Turn ignition switch to OFF.
2) Remove valve relay from relay box.
3) Measure resistance between valve relay 

terminals.

Terminals

No. 85 — No. 86:

Is the measured value within the specified 
range?

93 — 113 

Ω

Go to step 2.

Replace valve 
relay.

2

CHECK CONTACT POINT OF VALVE RE-
LAY.
1) Connect battery to valve relay terminals 

No. 85 and No. 86.

2) Measure resistance between valve relay 

terminals.

Terminals

No. 30 — No. 87:

Is the measured value less than the speci-
fied value?

0.5 

Ω

Go to step 3.

Replace valve 
relay.

3

CHECK CONTACT POINT OF VALVE RE-
LAY.
Measure resistance between valve relay termi-
nals.

Terminals

No. 30 — No. 87a:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 4.

Replace valve 
relay.

4

CHECK CONTACT POINT OF VALVE RE-
LAY.
1) Disconnect battery from valve relay termi-

nals.

2) Measure resistance between valve relay 

terminals.

Terminals

No. 30 — No. 87:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 5.

Replace valve 
relay.

5

CHECK CONTACT POINT OF VALVE RE-
LAY.
Measure resistance between valve relay termi-
nals.

Terminals

No. 30 — No. 87a:

Is the measured value less than the specified 
value?

0.5 

Ω

Go to step 6.

Replace valve 
relay.

6

CHECK SHORT OF VALVE RELAY.
Measure resistance between valve relay termi-
nals.

Terminals

No. 86 — No. 87:
No. 86 — No. 87a:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 7.

Replace valve 
relay.