Subaru Legacy (2005 year). Manual - part 815

VDC(diag)-125

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

Step

Check

Yes

No

1

CHECK PRESSURE SENSOR POWER SUP-
PLY.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from pressure 
sensor.
3) Turn the ignition switch to ON.
4) Measure the voltage between pressure 
sensor connector and chassis ground.

Connector & terminal

(B348) No. 3 (+) — Chassis ground (

−

):

Is the voltage 4.75 — 5.25 V?

Go to step 4.

Go to step 2.

2

CHECK OUTPUT VOLTAGE OF VDCCM&H/
U.
Measure the voltage between VDCCM&H/U 
and chassis ground.

Connector & terminal

(B310) No. 27 (+) — Chassis ground (

−

):

Is the voltage 4.75 — 5.25 V?

Repair the har-
ness between 
pressure sensor 
and VDCCM&H/U.

Go to step 3.

3

CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-

nector?

Correct or replace 
the connector.

Go to step 9.

4

CHECK GROUND CIRCUIT OF PRESSURE 
SENSOR.
Measure the resistance between pressure 
sensor and chassis ground.

Connector & terminal

(B348) No. 1 — Chassis ground:

Is the resistance less than 0.5 
Ω?

Go to step 7.

Go to step 5.

5

CHECK GROUND CIRCUIT OF VDCCM&H/U.
Measure the resistance between VDCCM&H/U 
and chassis ground.

Connector & terminal

(B310) No. 12 — Chassis ground:

Is the resistance less than 0.5 
Ω?

Repair the har-
ness between 
pressure sensor 
and VDCCM&H/U.

Go to step 6.

6

CHECK POOR CONTACT IN CONNECTORS. Is there poor contact in con-

nector?

Correct or replace 
the connector.

Go to step 9.

7

CHECK PRESSURE SENSOR HARNESS.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from VDCCM&H/
U.
3) Measure the resistance between 
VDCCM&H/U and pressure sensor.

Connector & terminal

(B310) No. 11 — (B348) No. 2:

Is the resistance less than 0.5 
Ω?

Go to step 8.

Repair the har-
ness between 
pressure sensor 
and VDCCM&H/U.

8

CHECK GROUND SHORT OF HARNESS.
Measure the resistance between VDCCM&H/U 
connector and chassis ground.

Connector & terminal

(B310) No. 11 — Chassis ground:

Is the resistance more than 1 
M

Ω?

Go to step 9.

Repair the har-
ness between 
pressure sensor 
and VDCCM&H/U.

9

CHECK VDCCM&H/U.
1) Connect all the connectors.
2) Perform the clear memory mode.
3) Perform the inspection mode.
4) Read the DTC.

Is DTC displayed?

Replace the 
VDCCM&H/U. 
<Ref. to VDC-7, 
VDC Control Mod-
ule and Hydraulic 
Control Unit 
(VDCCM&H/U).>

Go to step 10.

10

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to 
DTC.

Temporary poor 
contact occurs.

VDC(diag)-126

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BH:DTC C0074 EXCESSIVE PRESSURE SENSOR OUTPUT OFFSET

DTC DETECTING CONDITION:
Defective pressure sensor
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

VDC00223

27

11

12

B348

B348

1

2

3

B310

VDCCM & H/U

B310

1 2 3 4

11 12 13 14
27 28 29 30

15 16 17 18
31 32 33 34

19 20 21 22
35 36 37 38

23 24 25 26
39 40 41 42

5

6

7

8

9

10

1

2

3

PRESSURE SENSOR

VDC(diag)-127

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BI: DTC C0074 PRESSURE SENSOR POWER/OUTPUT

DTC DETECTING CONDITION:
Defective pressure sensor
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.

NOTE:
For the diagnostic procedure, refer to DTC C0074 “PRESSURE SENSOR TEST MALFUNCTION”. <Ref. to
VDC(diag)-124, DTC C0074 PRESSURE SENSOR TEST MALFUNCTION, Diagnostic Procedure with Di-
agnostic Trouble Code (DTC).>

Step

Check

Yes

No

1

CHECK STOP LIGHT SWITCH CIRCUIT.
Check stop light switch open circuit.

Is the stop light switch circuit 
OK?

Go to step 2.

Repair the stop 
light switch circuit.

2

CHECK VDCCM&H/U.
1) Connect all the connectors.
2) Perform the clear memory mode.
3) Perform the inspection mode.
4) Read the DTC.

Is the same DTC displayed?

Replace the 
VDCCM&H/U. 
<Ref. to VDC-7, 
VDC Control Mod-
ule and Hydraulic 
Control Unit 
(VDCCM&H/U).>

Go to step 3.

3

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to 
DTC. <Ref. to 
VDC(diag)-38, List 
of Diagnostic Trou-
ble Code (DTC).>

Temporary poor 
contact occurs.

VDC(diag)-128

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

BJ:DTC C0074 PRESSURE SENSOR OUTPUT

DTC DETECTING CONDITION:
Defective pressure sensor
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

Step

Check

Yes

No

1

CHECK STOP LIGHT SWITCH CIRCUIT.
Check stop light switch open circuit.

Is the stop light switch circuit 
OK?

Go to step 2.

If there is malfunc-
tion in the stop 
light switch circuit, 
DTC may be 
recorded in the 
memory.

VDC00223

27

11

12

B348

B348

1

2

3

B310

VDCCM & H/U

B310

1 2 3 4

11 12 13 14
27 28 29 30

15 16 17 18
31 32 33 34

19 20 21 22
35 36 37 38

23 24 25 26
39 40 41 42

5

6

7

8

9

10

1

2

3

PRESSURE SENSOR