Subaru Legacy III (2000-2003 year). Manual - part 756

VDC-60

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

N: DTC 29 ABNORMAL ABS SENSOR SIGNAL (ANY ONE OF FOUR)

DIAGNOSIS:
• Faulty ABS sensor signal (noise, irregular signal, etc.)
• Faulty tone wheel
• Wheels turning freely for a long time
TROUBLE SYMPTOM:
• ABS does not operate.
• VDC does not operate.
WIRING DIAGRAM:

VDC00174

F55

F88

B15

2 1

R72

R73

F45

4
1
3

F88

F45

B62

B100

F55

R49

B15

R73

R72

VDC CONTROL MODULE

FRONT ABS
SENSOR LH

FRONT ABS

SENSOR RH

LHD

RHD

REAR ABS

SENSOR LH

REAR ABS

SENSOR RH

F87

56 57

59 60

62 63

82 83

F87

: RHD MODEL

:LHD MODEL

4 5 6

1 2

3 4 5

6 7 8 9 10 11 12

1 2 3

4 5 6 7

8 9 10 11 12 13 14 15 16

3 4

1 2

8 9 10 11

12 13 14 15 16 17 18 19 20 21 22 23 24

5 6

VDC-61

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

Step

Value

Yes

CHECK IF THE WHEELS HAVE TURNED
FREELY.
Check if the wheels have been turned freely for
more than one minute, such as when the vehi-
cle is jacked-up, under full-lock cornering or
when tire is not in contact with road surface.

Turned freely over 1 minutes.

The VDC is nor-
mal. Erase the
diagnostic trouble
code.

NOTE:
When the wheels
turn freely for a
long time, such as
when the vehicle is
towed or jacked-
up, or when steer-
ing wheel is contin-
uously turned all
the way, this trou-
ble code may
sometimes occur.

Go to step 2.

CHECK TIRE SPECIFICATIONS.
Are the tire specifications correct?

Correct specification.

Go to step 3.

Replace tire.

CHECK WEAR OF TIRE.
Is the tire worn excessively?

Worn excesiblely.

Replace tire.

Go to step 4.

CHECK TIRE PRESSURE.
Is the tire pressure correct?

Correct tire pressure.

Go to step 5.

Adjust tire pres-
sure.

CHECK INSTALLATION OF ABS SENSOR.

Tightening torque:

±±±±

10 N·m (3.3

±±±±

1.0 kgf-m, 24

±±±±

7 ft-lb)

Are the ABS sensor installation bolts tightened
securely?

Tightened securely.

Go to step 6.

Tighten ABS sen-
sor installation
bolts securely.

CHECK ABS SENSOR GAP.
Measure tone wheel to pole piece gap over
entire perimeter of the wheel.
Is the measured value within the specified
range?

Front wheel 0.3 - 0.8 mm
(0.012 - 0.031 in) and Rear
wheel 0.44 - 0.94 mm (0.0173 -
0.0370 in)

Go to step 7.

Adjust the gap.

NOTE:
Adjust the gap us-
ing spacer (Part
No. 26755AA000).
If spacers cannot
correct the gap, re-
place worn sensor
or worn tone
wheel.

CHECK OSCILLOSCOPE.
Is an oscilloscope available?

Available.

Go to step 8.

Go to step 9.

CHECK ABS SENSOR SIGNAL.
1) Raise all four wheels of ground.
2) Turn ignition switch OFF.
3) Remove VDCCM connector cover. <Ref. to

VDC-19, VDCCM Connector Cover.>

4) Connect the oscilloscope to the connector.
5) Turn ignition switch ON.
6) Rotate wheels and measure voltage at

specified frequency. <Ref. to ABS-15,
WAVEFORM, Control Module I/O Signal.>

NOTE:

When this inspection is completed, the VDCCM
sometimes stores the DTC 29.

Connector & terminal

(F87) No. 14 (+) — No. 15 (

−−−−

) (Front RH):

(F87) No. 49 (+) — No. 19 (

−−−−

) (Front LH):

(F87) No. 18 (+) — No. 46 (

−−−−

) (Rear RH):

(F87) No. 16 (+) — No. 17 (

−−−−

) (Rear LH):

Is oscilloscope pattern smooth, as shown in
figure?

Smooth pattern.

Go to step 12.

Go to step 9.

VDC-62

VDC (DIAGNOSTICS)

DIAGNOSTICS CHART WITH DIAGNOSIS CONNECTOR

CHECK CONTAMINATION OF ABS SENSOR
OR TONE WHEEL.
Remove disc rotor from hub.
Is the ABS sensor pole piece or the tone wheel
contaminated by dirt or other foreign matter?

Dirt or foreign matter found.

Thoroughly
remove dirt or
other foreign mat-
ter.

Go to step 10.

CHECK DAMAGE OF ABS SENSOR OR
TONE WHEEL.
Are there broken or damaged teeth in the ABS
sensor pole piece or the tone wheel?

Broken or damaged.

Replace ABS sen-
sor or tone wheel.
Front <Ref. to
VDC-27, Front
ABS Sensor.> and
<Ref. to VDC-29,
Front Tone
Wheel.> Rear
<Ref. to VDC-28,
Rear ABS Sen-
sor.> an d <Ref. to
VDC-30, Rear
Tone Wheel.>

Go to step 11.

CHECK TONE WHEEL RUNOUT.
Measure tone wheel runout.
Is the measured value less than the specified
value?

0.05 mm (0.0020 in)

Go to step 12.

Repair tone wheel.
Front <Ref. to
VDC-29, Front
Tone Wheel.>
Rear <Ref. to
VDC-30, Rear
Tone Wheel.>

CHECK VDCCM.
1) Turn ignition switch to OFF.
2) Connect all connectors.
3) Erase the memory.
4) Perform inspection mode.
5) Read out the diagnostic trouble code.

Is the diagnostic same 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 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

VDC-63