Subaru Legacy III (2000-2003 year). Manual - part 786

VDC-180

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

AD:DTC 45 TCM MALFUNCTION SPECIFICATIONS

DIAGNOSIS:
• Control module out of specification
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.

Step

Value

Yes

No

1

CHECK AT SYSTEM.
1) Start the engine.
2) Check AT system diagnostic trouble code.

Is the AT system diagnostic trouble code is 
same with the specification?

Indicated.

Repair AT system. Replace VDCCM.  

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

VDC-181

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

MEMO:

VDC-182

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

AE:DTC 46 ABNORMAL VOLTAGE OF 5 V POWER SUPPLY

DIAGNOSIS:
• 5 volt power supply is abnormal.
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

VDC00177

VDC CONTROL MODULE

63

70

64

76

77

78

15

13

16

36

14

5

3

6

10

12

9

F87

YAW RATE AND

LATERAL G SENSOR

F55

R49

R100

VDC HYDRAULIC UNIT

F91

VDC5

PRIMAR

Y 

PRESSURE SENSOR

SECOND

AR

Y 

PRESSURE SENSOR

F55

1 2 3

4 5

6 7 8 9 10 11 12

F91

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

R100

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

3

4 5 6

2

VDC-183

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

Step

Value

Yes

No

1

CHECK GROUND SHORT OF SENSOR AND 
HARNESS.
1) Turn ignition switch OFF.
2) Disconnect connector from VDCCM.
3) Measure resistance between VDCCM con-

nector and chassis ground.

Connector & terminal

(F87) No. 63 — Chassis ground (Lateral 
G sensor):
(F87) No. 78 — Chassis ground (Pres-
sure sensor):

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 3.

Go to step 2.

2

CHECK GROUND SHORT OF HARNESS.
1) Disconnect connector from faulty sensors.
2) Measure resistance between VDCCM and 

chassis ground.

Connector & terminal

(F87) No. 63 — Chassis ground (Lateral 
G sensor):
(F87) No. 78 — Chassis ground (Pres-
sure sensor):

Does the measured value exceed the spec-
ified value?

1 M

Ω

Replace faulty 
sensors.

Repair or replace 
harness connec-
tor between 
VDCCM and faulty 
sensor.

3

CHECK BATTERY SHORT OF SENSOR AND 
HARNESS.
Measure voltage between VDCCM and chas-
sis ground.

Connector & terminal

(F87) No. 63 (+) — Chassis ground (

−−−−

) 

(Lateral G sensor):
(F87) No. 78 (+) — Chassis ground (

−−−−

) 

(Pressure sensor):

Is the measured value less than the specified 
value?

0.5 V

Go to step 4.

Go to step 5.

4

CHECK BATTERY SHORT OF SENSOR AND 
HARNESS.
1) Turn ignition switch to ON.
2) Measure voltage between VDCCM connec-

tor and chassis ground.

Connector & terminal

(F87) No. 63 (+) — Chassis ground (

−−−−

) 

(Lateral G sensor):
(F87) No. 78 (+) — Chassis ground (

−−−−

) 

(Pressure sensor):

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

0.5 V

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

Go to step 5.

5

CHECK BATTERY SHORT OF HARNESS.
1) Turn ignition switch to OFF.
2) Disconnect connector from faulty sensors.
3) Measure voltage between VDCCM and 

chassis ground.

Connector & terminal

(F87) No. 63 (+) — Chassis ground (

−−−−

) 

(Lateral G sensor):
(F87) No. 78 (+) — Chassis ground (

−−−−

) 

(Pressure sensor):

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

0.5 V

Go to step 6.

Repair or replace 
harness connec-
tor between 
VDCCM and faulty 
sensor.