Subaru Legacy (2005 year). Service manual — part 779

VDC-5

VEHICLE DYNAMICS CONTROL (VDC)

General Description

4. VDC CONTROL MODULE AND HYDRAULIC CONTROL UNIT (VDCCM&H/U)

C: CAUTION

• Wear work clothing, including a cap, protective
goggles and protective shoes during operation.
• Remove contamination including dirt and corro-
sion before removal, installation or disassembly.
• Keep the disassembled parts in order and pro-
tect them from dust and dirt.
• Before disconnecting connectors of sensors or
units, be sure to disconnect the ground cable from
battery.
• Before removal, installation or disassembly, be
sure to clarify the failure. Avoid unnecessary re-
moval, installation, disassembly and replacement.
• Be careful not to burn yourself, because each
part on the vehicle is hot after running.
• Be sure to tighten fasteners including bolts and
nuts to the specified torque.
• Place shop jacks or rigid racks at the specified
points.

(1)

VDC control module & hydraulic
control unit (VDCCM&H/U)

(5)

Rear LH outlet

(10)

Pressure sensor

(6)

Secondary inlet

(11)

Damper

(2)

Clip

(7)

Primary inlet

(3)

Bracket

(8)

Front LH outlet

Tightening torque: N

⋅

m (kgf-m, ft-lb)

(4)

Rear RH outlet

(9)

Front RH outlet

T: 33 (3.4, 24.3)

VDC00197

T

T

(9)

(8) (7)

(6)

(5)

(4)

(10)

(1)

(2)

(3)

T

(11)

T

VDC-6

VEHICLE DYNAMICS CONTROL (VDC)

General Description

D: PREPARATION TOOL

1. SPECIAL TOOL

2. GENERAL TOOL

ILLUSTRATION

TOOL NUMBER

DESCRIPTION

REMARKS

18482AA000

(Newly adopted tool)

CARTRIDGE

Troubleshooting for electrical system.

22771AA030

SUBARU SELECT
MONITOR KIT

Troubleshooting for electrical system.
• English: 22771AA030 (Without printer)
• German: 22771AA070 (Without printer)
• French: 22771AA080 (Without printer)
• Spanish: 22771AA090 (Without printer)

TOOL NAME

REMARKS

Circuit tester

Used for measuring resistance, voltage and current.

Pressure gauge

Used for measuring oil pressure.

Oscilloscope

Used for measuring sensor.

ST18482AA000

ST22771AA030

VDC-7

VEHICLE DYNAMICS CONTROL (VDC)

VDC Control Module and Hydraulic Control Unit (VDCCM&H/U)

2. VDC Control Module and Hy-

draulic Control Unit (VDC-
CM&H/U)

A: REMOVAL

1) Disconnect the ground cable from battery.
2) Use compressed air to get rid of water and dust
around the VDCCM&H/U.

NOTE:
When dust and dirt are attached to the terminal,
they may cause poor contact.
3) Disconnect the pressure sensor connector.

4) Disconnect the VDCCM&H/U connector with
pulling up the lock lever.

CAUTION:
Do not pull the harness when disconnecting
connector.

5) Disconnect the brake pipes from VDCCM&H/U.
6) Wrap the brake pipe using a vinyl bag not to spill
the brake fluid on the vehicle body.

CAUTION:
When brake fluid is attached to the vehicle
body, wash it off with water and wipe the water.

7) Remove the clips, and then remove the VDC-
CM&H/U.

CAUTION:
• VDCCM&H/U cannot be disassembled. Do
not attempt to loosen the bolts and nuts.
• Do not drop or bump the VDCCM&H/U.
• Do not turn VDCCM&H/U upside down or
place it sideways for storage.
• Be careful that no foreign objects are mixed
in VDCCM&H/U.
• Be careful that no water enters inside the
connectors.

8) Remove the VDCCM&H/U bracket.

B: INSTALLATION

1) Install the VDCCM&H/U bracket.

Tightening torque:

33 N

⋅

m (3.4 kgf-m, 24.3 ft-lb)

2) Install the VDCCM&H/U to bracket.
3) Install the clip.

NOTE:
Hook the clip on the pawl of bracket securely.

VDC00198

VDC00199

VDC00201

VDC00200

VDC00201

VDC-8

VEHICLE DYNAMICS CONTROL (VDC)

VDC Control Module and Hydraulic Control Unit (VDCCM&H/U)

4) Connect the brake pipes to their specified VDC-
CM&H/U positions.

Tightening torque:

T1: 15 N

⋅

m (1.5 kgf-m, 11.1 ft-lb)

T2: 19 N

⋅

m (1.9 kgf-m, 14 ft-lb)

5) Connect the VDCCM&H/U connector.

NOTE:
• Be sure to remove all foreign matters from inside
the connector before connecting.
• Ensure that the VDCCM&H/U connector is se-
curely locked.
6) Connect the pressure sensor connector.
7) Bleed air from brake system.

C: INSPECTION

1) Check the connected and fixed condition of con-
nector.
2) Check the mark used for VDCCM&H/U identifi-
cation.
Refer to “SPECIFICATION” for mark. <Ref. to
VDC-2, SPECIFICATION, General Description.>

1. CHECKING THE HYDRAULIC UNIT ABS
OPERATION BY PRESSURE GAUGE

<Ref. to ABS-7, CHECKING THE HYDRAULIC
UNIT ABS OPERATION BY PRESSURE GAUGE,
INSPECTION, ABS Control Module and Hydraulic
Control Unit (ABSCM&H/U).>

2. CHECKING THE HYDRAULIC UNIT ABS
OPERATION WITH BRAKE TESTER

<Ref. to ABS-8, CHECKING THE HYDRAULIC
UNIT ABS OPERATION WITH BRAKE TESTER,
INSPECTION, ABS Control Module and Hydraulic
Control Unit (ABSCM&H/U).>

3. CHECKING THE HYDRAULIC UNIT VDC
OPERATION BY PRESSURE GAUGE

1) Lift-up the vehicle, and then remove the wheels.
2) Remove the air bleeder screws from the FL and
FR caliper bodies.
3) Connect two pressure gauges to the FL and FR
caliper bodies.

CAUTION:
• Pressure gauges used exclusively for brake
fluid must be used.
• Do not use the pressure gauge for the mea-
surement of transmission oil pressure since
the piston seal may be expanded and de-
formed.

NOTE:
Wrap a sealing tape around the pressure gauge.

4) Bleed air from the pressure gauges.
5) Perform VDC sequence control.
<Ref. to VDC-12, VDC Sequence Control.>
6) When the hydraulic unit begins to work, first the
FL side performs compression, holding, and de-
compression, and then the FR side performs com-
pression, holding, and decompression.
7) Read values indicated on the pressure gauge
and check if the fluctuation of the values between
decompression and compression meets specifica-
tion. Depress the brake pedal and check that it is
not abnormally hard, and tightness is normal.

(1) Identification mark

T2

VDC00311

T1

T1

T2

VDC00202

(1)

Front wheel

Rear wheel

When com-
pressed

3,000 kPa

(31 kgf/cm

2

, 441

psi) or more

3,000 kPa

(31 kgf/cm

2

, 441

psi) or more

When decom-
pressed

500 kPa

(5 kgf/cm

2

, 73 psi)

or less

500 kPa

(5 kgf/cm

2

, 73 psi)

or less

ABS00134