Subaru Legacy III (2000-2003 year). Manual - part 780

VDC-156

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

V: DTC 64 NORMAL CLOSING VALVE 1 MALFUNCTION (SECONDARY SUC-

TION VALVE MALFUNCTION)

DIAGNOSIS:
• Faulty harness/connector
• Faulty solenoid valve in VDCH/U
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

VDC00142

VDC1

1 2

F91

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

10

9

11

12

15

13

16

14

VDC HYDRAULIC UNIT

VDC5

F91

VDC CONTROL MODULE

F87

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

VDC2

VDC1

1
2

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

RELAY BOX

MOTOR RELAY

VALVE RELAY

VDC-157

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

Step

Value

Yes

No

1

CHECK RESISTANCE OF SOLENOID 
VALVE.
1) Turn ignition switch to OFF.
2) Disconnect two connectors (VDC1, F91) 

from VDCH/U.

3) Measure resistance between VDCH/U con-

nector terminals.

Connector & terminal

DTC 32/(VDC5) No. 1 — (VDC2) No. 2:
DTC 34/(VDC5) No. 4 — (VDC2) No. 2:
DTC 36/(VDC5) No. 3 — (VDC2) No. 2:
DTC 38/(VDC5) No. 2 — (VDC2) No. 2:
DTC 63/(VDC5) No. 10 — (VDC2) No. 2:
DTC 64/(VDC5) No. 11 — (VDC2) No. 2:

Is the measured value within the specified 
range?

3.8 — 4.8 

Ω

Go to step 2.

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

2

CHECK GROUND SHORT OF SOLENOID 
VALVE.
Measure resistance between VDCH/U connec-
tor and chassis ground.

Connector & terminal

DTC 32/(VDC5) No. 1 — Chassis 
ground:
DTC 34/(VDC5) No. 4 — Chassis 
ground:
DTC 36/(VDC5) No. 3 — Chassis 
ground:
DTC 38/(VDC5) No. 2 — Chassis 
ground:
DTC 63/(VDC5) No. 10 — Chassis 
ground:
DTC 64/(VDC5) No. 11 — Chassis 
ground:

Does the measured value exceed the specified 
value?

1 M

Ω

Go to step 3.

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

3

CHECK BATTERY SHORT OF SOLENOID 
VALVE.
1) Disconnect connector from VDCCM.
2) Measure voltage between VDCH/U con-

nector and chassis ground.

Connector & terminal

DTC 32/(VDC5) No. 1 (+) — Chassis 
ground (

−−−−

):

DTC 34/(VDC5) No. 4 (+) — Chassis 
ground (

−−−−

):

DTC 36/(VDC5) No. 3 (+) — Chassis 
ground (

−−−−

):

DTC 38/(VDC5) No. 2 (+) — Chassis 
ground (

−−−−

):

DTC 63/(VDC5) No. 10 (+) — Chassis 
ground (

−−−−

):

DTC 64/(VDC5) No. 11 (+) — Chassis 
ground (

−−−−

):

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

1 V

Go to step 4.

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

VDC-158

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

4

CHECK BATTERY SHORT OF SOLENOID 
VALVE.
1) Turn ignition switch to ON.
2) Measure voltage between VDCH/U con-

nector and chassis ground.

Connector & terminal

DTC 32/(VDC5) No. 1 (+) — Chassis 
ground (

−−−−

):

DTC 34/(VDC5) No. 4 (+) — Chassis 
ground (

−−−−

):

DTC 36/(VDC5) No. 3 (+) — Chassis 
ground (

−−−−

):

DTC 38/(VDC5) No. 2 (+) — Chassis 
ground (

−−−−

):

DTC 63/(VDC5) No. 10 (+) — Chassis 
ground (

−−−−

):

DTC 64/(VDC5) No. 11 (+) — Chassis 
ground (

−−−−

):

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

1 V

Go to step 5.

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

5

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

tor and chassis ground.

Connector & terminal

DTC 32/(F87) No. 3 (+) — Chassis 
ground (

−−−−

):

DTC 34/(F87) No. 51 (+) — Chassis 
ground (

−−−−

):

DTC 36/(F87) No. 50 (+) — Chassis 
ground (

−−−−

):

DTC 38/(F87) No. 4 (+) — Chassis 
ground (

−−−−

):

DTC 63/(F87) No. 29 (+) — Chassis 
ground (

−−−−

):

DTC 64/(F87) No. 2 (+) — Chassis 
ground (

−−−−

):

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

1 V

Go to step 6.

Repair harness 
between VDCCM 
and VDCH/U.

6

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

tor and chassis ground.

Connector & terminal

DTC 32/(F87) No. 3 (+) — Chassis 
ground (

−−−−

):

DTC 34/(F87) No. 51 (+) — Chassis 
ground (

−−−−

):

DTC 36/(F87) No. 50 (+) — Chassis 
ground (

−−−−

):

DTC 38/(F87) No. 4 (+) — Chassis 
ground (

−−−−

):

DTC 63/(F87) No. 29 (+) — Chassis 
ground (

−−−−

):

DTC 64/(F87) No. 2 (+) — Chassis 
ground (

−−−−

):

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

1 V

Go to step 7.

Repair harness 
between VDCCM 
and VDCH/U.

Step

Value

Yes

No

VDC-159

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

7

CHECK GROUND SHORT OF HARNESS.
1) Turn ignition switch to OFF.
2) Measure resistance between VDCCM con-

nector and chassis ground.

Connector & terminal

DTC 32/(F87) No. 3 — Chassis ground:
DTC 34/(F87) No. 51 — Chassis ground:
DTC 36/(F87) No. 50 — Chassis ground:
DTC 38/(F87) No. 4 — Chassis ground:
DTC 63/(F87) No. 29 — Chassis ground:
DTC 64/(F87) No. 2 — Chassis ground:

Does the measured value exceed the spec-
ified value?

1 M

Ω

Go to step 8.

Repair harness 
between VDCCM 
and VDCH/U.

8

CHECK HARNESS/CONNECTOR BETWEEN 
VDCCM AND VDCH/U.
1) Connect connector (F91) to VDCH/U.
2) Measure resistance between VDCCM con-

nector and VDCH/U connector.

Connector & terminal

DTC 32/(F87) No. 3 — (VDC2) No. 1:
DTC 34/(F87) No. 51 — (VDC2) No. 1:
DTC 36/(F87) No. 50 — (VDC2) No. 1:
DTC 38/(F87) No. 4 — (VDC2) No. 1:
DTC 63/(F87) No. 29 — (VDC2) No. 1:
DTC 64/(F87) No. 2 — (VDC2) No. 1:

Is the measured value within the specified 
range?

3 — 6 

Ω

Go to step 9.

Repair harness/
connector 
between VDCCM 
and VDCH/U.

9

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

Tightened securely.

Repair connector.

Go to step 10.

10

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?

There is poor contact.

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

Go to step 11.

11

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

Same DTC indicated.

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

A temporary poor 
contact.

Step

Value

Yes

No