Subaru Legacy III (2000-2003 year). Manual - part 781

VDC-160

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

W: DTC 41 ELECTRICAL CONTROL MODULE (VDC CONTROL MODULE MAL-

FUNCTION)

DIAGNOSIS:
• Faulty VDCCM
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

VDC00143

VDC

CONTROL

MODULE

1

55

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

F87

VDC-161

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

Step

Value

Yes

No

1

CHECK GROUND CIRCUIT OF VDCCM.
1) Turn ignition switch to OFF.
2) Disconnect connector from VDCCM.
3) Measure resistance between VDCCM and 

chassis ground.

Connector & terminal

(F87) No. 1 — Chassis ground:
(F87) No. 55 — Chassis ground:

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

0.5 

Ω

Go to step 2.

Repair VDCCM 
ground harness.

2

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connectors between 
battery, ignition switch and VDCCM?

There is poor contact.

Repair connector.

Go to step 3.

3

CHECK SOURCES OF SIGNAL NOISE.
Is the car telephone or the wireless transmitter 
properly installed?

Tightened securely.

Go to step 4.

Properly install the 
car telephone or 
the wireless trans-
mitter.

4

CHECK SOURCES OF SIGNAL NOISE.
Are noise sources (such as an antenna) 
installed near the sensor harness?

Installed properly.

Install the noise 
sources apart from 
the sensor har-
ness.

Go to step 5.

5

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 6.

6

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-162

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

X: DTC 42 POWER SUPPLY VOLTAGE LOW

DIAGNOSIS:
• Power source voltage of the VDCCM is low.
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

VDC00144

VDC CONTROL MODULE

1

55

28

F87

SBF-1

GENERATOR

SBF-4

IGNITION 
SWITCH

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

BATTERY

NO

. 18 15A

VDC-163

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH SELECT MONITOR

Step

Value

Yes

No

1

CHECK GENERATOR.
1) Start engine.
2) Idling after warm-up.
3) Measure voltage between generator B ter-

minal and chassis ground.

Terminal

Generator B terminal (

++++

) — Chassis 

ground (

−−−−

):

Is the measured value within the specified 
range?

10 — 15 V

Go to step 2.

Repair generator.

2

CHECK BATTERY TERMINAL.
Turn ignition switch to OFF.
Are the positive and negative battery terminals 
tightly clamped?

Clamped securely.

Go to step 3.

Tighten the clamp 
of terminal.

3

CHECK INPUT VOLTAGE OF VDCCM.
1) Disconnect connector from VDCCM.
2) Run the engine at idle.
3) Measure voltage between VDCCM connec-

tor and chassis ground.

Connector & terminal

(F87) No. 28 (+) — Chassis ground (

−−−−

):

Is the measured value within the specified 
range?

10 — 15 V

Go to step 4.

Repair harness 
connector 
between battery, 
ignition switch and 
VDCCM.

4

CHECK GROUND CIRCUIT OF VDCCM.
1) Turn ignition switch to OFF.
2) Measure resistance between VDCCM and 

chassis ground.

Connector & terminal

(F87) No. 1 — Chassis ground:
(F87) No. 55 — Chassis ground:

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

0.5 

Ω

Go to step 5.

Repair VDCCM 
ground harness.

5

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

There is poor contact.

Repair connector.

Go to step 6.

6

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 7.

7

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.