Subaru Legacy III (2000-2003 year). Service manual — part 772

VDC-124

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

7

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

tor and chassis ground.

Connector & terminal

(F87) No. 63 (+) — Chassis ground (

−−−−

):

(F87) No. 70 (+) — Chassis ground (

−−−−

):

(F87) No. 64 (+) — Chassis ground (

−−−−

):

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

1 V

Go to step 8.

Repair harness
between yaw rate
and lateral G sen-
sor and VDCCM.

8

CHECK LATERAL G SENSOR.
1) Turn ignition switch to OFF.
2) Remove yaw rate and lateral G sensor from

vehicle.

3) Connect connector to yaw rate and lateral

G sensor.

4) Connect connector to VDCCM.
5) Turn ignition switch to ON.
6) Measure voltage between yaw rate and lat-

eral G sensor connector terminals.

Connector & terminal

(R100) No. 5 (+) — No. 6 (

−−−−

):

Is the measured value within the specified
range when yaw rate and lateral G sensor
is horizontal?

2.3 — 2.7 V

Go to step 9.

Replace yaw rate
and lateral G sen-
sor. <Ref. to VDC-
22, Yaw Rate and
Lateral G Sensor.>

9

CHECK YAW RATE AND LATERAL G SEN-
SOR.
Measure voltage between yaw rate and lateral
G sensor connector terminals.

Connector & terminal

(R100) No. 5 (+) — No. 6 (

−−−−

):

Is the measured value within the specified
range when yaw rate and lateral G sensor is
inclined 90

°

to left?

3.3 — 3.7 V

Go to step 10.

Replace yaw rate
and lateral G sen-
sor. <Ref. to VDC-
22, Yaw Rate and
Lateral G Sensor.>

10

CHECK YAW RATE AND LATERAL G SEN-
SOR.
Measure voltage between yaw rate and lateral
G sensor connector terminals.

Connector & terminal

(R100) No. 5 (+) — No. 6 (

−−−−

):

Is the measured value within the specified
range when yaw rate and lateral G sensor is
inclined 90

°

to right?

1.3 — 1.7 V

Go to step 11.

Replace yaw rate
and lateral G sen-
sor. <Ref. to VDC-
22, Yaw Rate and
Lateral G Sensor.>

11

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in connector between
VDCCM and yaw rate and lateral G sensor?

There is poor contact.

Repair connector.

Go to step 12.

12

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 pattern.

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

Go to step 13.

13

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.

Step

Value

Yes

No

VDC-125

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

MEMO:

VDC-126

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

AO:DTC 74 ABNORMAL PRESSURE SENSOR

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

VDC00181

78

36

77

76

F91

VDC5

F88

2
3

F88

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

VDC HYDRAULIC

UNIT

PRIMAR

Y

PRESSURE SENSOR

SECOND

AR

Y

PRESSURE SENSOR

15

13

16

14

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

F87

VDC

CONTROL

MODULE

1

3

4 5 6

2

VDC-127

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

Step

Value

Yes

No

1

CHECK GROUND CIRCUIT OF PRESSURE
SENSOR.
1) Turn ignition switch to OFF.
2) Disconnect connector (F91) from VDCH/U.
3) Measure resistance between VDCH/U con-

nector and chassis ground.

Connector & terminal

(F91) No. 15 — Chassis ground:

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

0.5

Ω

Go to step 4.

Go to step 2.

2

CHECK GROUND CIRCUIT OF VDCCM.
1) Disconnect connector from VDCCM.
2) Remove cover from VDCCM. <Ref. to

VDC-19, REMOVE, VDCCM Connector
Cover.>

3) Connect connector to VDCCM.
4) Measure resistance between VDCCM and

chassis ground.

Connector & terminal

(F87) No. 76 — Chassis ground:

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

0.5

Ω

Replace harness
between VDCH/U
and VDCCM.

Go to step 3.

3

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in VDCCM connector?

There is poor contact.

Repair or replace
VDCCM connec-
tor.

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

4

CHECK POWER SUPPLY OF PRESSURE
SENSOR.

NOTE:

When this inspection is carried out, DTC 51 AB-
NORMAL VALVE RELAY is memorized, but
this does not indicate valve relay malfunction.

1) Turn ignition switch to ON.
2) Measure voltage between VDCH/U con-

nector terminals.

Connector & terminal

(F91) No. 16 (+) — No. 15 (

−−−−

):

Is the measured value within the specified
range?

4.75 — 5.25 V

Go to step 7.

Go to step 5.

5

CHECK POWER SUPPLY OF VDCCM.
1) Turn ignition switch to OFF.
2) Disconnect connector from VDCCM.
3) Remove cover from VDCCM. <Ref. to

VDC-19, REMOVE, VDCCM Connector
Cover.>

4) Connect connector to VDCCM.
5) Turn ignition switch to ON.
6) Measure voltage between VDCCM connec-

tor terminals.

Connector & terminal

(F87) No. 78 (+) — No. 76 (

−−−−

):

Is the measured value within the specified
range?

4.75 — 5.25 V

Repair harness
between VDCH/U
and VDCCM.

Go to step 6.

6

CHECK POOR CONTACT IN CONNECTORS.
Is there poor contact in VDCCM connector?

There is poor contact.

Repair or replace
VDCCM connec-
tor.

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