Subaru Legacy IV (2008 year). Service manual — part 932

VDC(diag)-43

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

H: DTC C0028 REAR LEFT ABS SENSOR SIGNAL

DTC DETECTING CONDITION:
• Defective ABS wheel speed sensor signal (noise, irregular signal, etc.)
• Defective harness connector
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

4

3

1

26

27

2

25

B98

R72

R2

E

1

2

15

14

6

5

R73

1

2

B6

B15

R73

R72

1

2

1 2

2 1

6

5

B310

2

1

B15

B6

VDCCM & H/U

B310

4 5 6 7 8 9

26 27 28 29 30

2 3

1

31 32 33 34 35 36

10 11

14 15 16 17 18 19

37 38 39 40

12 13

41 42 43 44 45 46

20 21

23

24

22

25

VDC00501

B98

1 2 3

4 5 6 7

8 9 10 11 12 13 14 15 16

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

FRONT ABS

WHEEL SPEED

SENSOR LH

FRONT ABS

WHEEL SPEED

SENSOR RH

REAR ABS

WHEEL SPEED

SENSOR LH

REAR ABS

WHEEL SPEED

SENSOR RH

VDC(diag)-44

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Step

Check

Yes

No

1

CHECK OUTPUT OF ABS WHEEL SPEED
SENSOR USING SUBARU SELECT MONI-
TOR.
1) Select {Current Data Display & Save} in the
Subaru Select Monitor.
2) Read the defective ABS wheel speed sen-
sor output.

Does the speed indicated on
the display change in response
to the speedometer reading
during acceleration/decelera-
tion when the steering wheel is
in the straight-ahead position?

Go to step 2.

Go to step 7.

2

CHECK POOR CONTACT IN CONNECTOR.
Turn the ignition switch to OFF.

Is there poor contact in connec-
tors between VDCCM&H/U and
ABS wheel speed sensor?

Repair the connec-
tor.

Go to step 3.

3

CHECK CAUSE OF SIGNAL NOISE.
Make sure the radio wave devices and elec-
tronic components are installed correctly.

Are the radio wave devices and
electronic components
installed correctly?

Go to step 4.

Install the radio
wave devices and
electronic compo-
nents properly.

4

CHECK CAUSE OF SIGNAL NOISE.
Check if the noise sources (such as an
antenna) are installed near the sensor harness.

Are noise sources installed?

Install the noise
sources apart from
sensor harness.

Go to step 5.

5

CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-23,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-22, PROCEDURE, Inspection
Mode.>
4) Read the DTC.

Is the same DTC displayed?

Replace the
VDCCM only.
<Ref. to VDC-10,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Go to step 6.

6

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-34, List
of Diagnostic Trou-
ble Code (DTC).>

It results from a
temporary noise
interference.

7

CHECK INSTALLATION OF ABS WHEEL
SPEED SENSOR.

Is the ABS wheel speed sensor
installation bolt tightened 7.5 N·m
(0.76 kgf-m, 5.5 ft-lb)?

Go to step 8.

Tighten the ABS
wheel speed sen-
sor installation
bolts.

8

CHECK ABS WHEEL SPEED SENSOR SIG-
NAL.
1) Install the ABS wheel speed sensor.
2) Prepare an oscilloscope.
3) Check the ABS wheel speed sensor. <Ref.
to ABS-14, ABS WHEEL SPEED SENSOR,
INSPECTION, Front ABS Wheel Speed Sen-
sor.>

Does the oscilloscope indicate
the waveform pattern like
shown in the figure when the
tire is slowly turned? Does the
oscilloscope indication repeat
the waveform pattern like
shown in the figure when the
tire is slowly turned in equal
speed for one rotation or more?

Go to step 10.

Go to step 9.

9

CHECK ABS WHEEL SPEED SENSOR OR
MAGNETIC ENCODER.

Are there foreign matter, break-
age or damage at the tip of ABS
wheel speed sensor or mag-
netic encoder?

Remove dirt thor-
oughly. Also
replace the ABS
wheel speed sen-
sor or magnetic
encoder as a unit
with hub unit bear-
ing if it is broken or
damaged.

Go to step 10.

10

CHECK CAUSE OF SIGNAL NOISE.
Make sure the radio wave devices and elec-
tronic components are installed correctly.

Are the radio wave devices and
electronic components
installed correctly?

Go to step 11.

Install the radio
wave devices and
electronic compo-
nents properly.

VDC(diag)-45

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

11

CHECK CAUSE OF SIGNAL NOISE.
Check if the noise sources (such as an
antenna) are installed near the sensor harness.

Is the noise sources installed? Go to step 12.

Install the noise
sources apart from
sensor harness.

12

CHECK VDCCM&H/U.
1) Connect all connectors.
2) Clear the memory. <Ref. to VDC(diag)-23,
Clear Memory Mode.>
3) Perform the Inspection Mode. <Ref. to
VDC(diag)-22, PROCEDURE, Inspection
Mode.>
4) Read the DTC.

Is the same DTC displayed?

Replace the
VDCCM only.
<Ref. to VDC-10,
REPLACEMENT,
VDC Control Mod-
ule and Hydraulic
Control Unit
(VDCCM&H/U).>

Go to step 13.

13

CHECK OTHER DTC DETECTION.

Is any other DTC displayed?

Perform the diag-
nosis according to
DTC. <Ref. to
VDC(diag)-34, List
of Diagnostic Trou-
ble Code (DTC).>

It results from a
temporary noise
interference.

NOTE:
Though the ABS
warning light re-
mains on at this
time, this is normal.
Drive the vehicle at
12 km/h (7 MPH)
or more in order to
turn ABS warning
light off. Be sure to
drive the vehicle
and check that the
warning light goes
off.

Step

Check

Yes

No

VDC(diag)-46

Diagnostic Procedure with Diagnostic Trouble Code (DTC)

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

I:

DTC C0029 ANY OF WHEEL SENSORS SIGNAL

DTC DETECTING CONDITION:
• Defective ABS wheel speed sensor signal (noise, irregular signal, etc.)
• Defective magnetic encoder
• When a wheel is turned freely for a long time
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
• EBD may not operate.

NOTE:
Brake warning light illuminates as well as ABS warning light when EBD does not operate.
WIRING DIAGRAM:

4

3

1

26

27

2

25

B98

R72

R2

E

1

2

15

14

6

5

R73

1

2

B6

B15

R73

R72

1

2

1 2

2 1

6

5

B310

2

1

B15

B6

VDCCM & H/U

B310

4 5 6 7 8 9

26 27 28 29 30

2 3

1

31 32 33 34 35 36

10 11

14 15 16 17 18 19

37 38 39 40

12 13

41 42 43 44 45 46

20 21

23

24

22

25

VDC00501

B98

1 2 3

4 5 6 7

8 9 10 11 12 13 14 15 16

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

TWISTED P

AIR LINE

FRONT ABS

WHEEL SPEED

SENSOR LH

FRONT ABS

WHEEL SPEED

SENSOR RH

REAR ABS

WHEEL SPEED

SENSOR LH

REAR ABS

WHEEL SPEED

SENSOR RH