Subaru Legacy (2005 year). Manual - part 785

VDC(diag)-5

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Check List for Interview

2. STATE OF VDC WARNING LIGHT AND VDC OFF INDICATOR LIGHT

3. STATE OF VDC OPERATION INDICATOR LIGHT

VDC warning light 
and VDC OFF indi-
cator light come on.

❏ Always

❏ Sometimes

❏ Only once

❏ Not come on

• When / How long does it come on?

Ignition key position

❏ LOCK

❏ ACC

❏ ON (before starting engine)

❏ START

❏ ON (after engine starting, engine is running)

❏ ON (after engine starting, engine is at a standstill)

Timing

❏ Immediately after turning the ignition switch to ON

❏ Immediately after turning the ignition switch to START
❏ When accelerating

—

km/h

—

MPH

❏ When driving at a constant speed

km/h

MPH

❏ When decelerating

—

km/h

—

MPH

❏ When turning to the right

Steering angle:

deg

Steering time:

Sec.

❏ When turning to the left

Steering angle:

deg

Steering time:

Sec.

❏ When operating other electrical parts
• Part name:

• Operating condition:

VDC operation indi-
cator light comes on.

❏ Always

❏ Sometimes

❏ Only once

❏ Not come on

• When / How long does it come on?

Ignition key position

❏ LOCK

❏ ACC

❏ ON (before starting engine)

❏ START

❏ ON (after engine starting, engine is running)

❏ ON (after engine starting, engine is at a standstill)

Timing

❏ Immediately after turning the ignition switch to ON

❏ Immediately after turning the ignition switch to START
❏ When accelerating

—

km/h

—

MPH

❏ When driving at a constant speed

km/h

MPH

❏ When decelerating

—

km/h

—

MPH

❏ When turning to the right

Steering angle:

deg

Steering time:

Sec.

❏ When turning to the left

Steering angle:

deg

Steering time:

Sec.

❏ When operating other electrical parts
• Part name:

• Operating condition:

VDC(diag)-6

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Check List for Interview

4. CONDITIONS UNDER WHICH TROUBLE OCCURS

Environment

a) Weather

❏ Fine

❏ Cloudy

❏ Rainy

❏ Snowy

❏ Others:

b) Ambient temperature

°C (°F)

c) Road

❏ Inner city

❏ Suburbs

❏ Highway

❏ Local street

❏ Uphill

❏ Downhill

❏ Paved road

❏ Gravel road

❏ Muddy road

❏ Sandy place

❏ Straight road

❏ Sharp curve

❏ Gentle curve

❏ S-curve

❏ Road with a slope on both sides

❏ Others:

d) Road surface

❏ Dried

❏ Wet

❏ Covered with fresh snow

❏ Covered with hardened snow

❏ Frozen slope

❏ Others:

VDC(diag)-7

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Check List for Interview

Condition

a) Brakes

Deceleration:

G

❏ continuous / ❏ intermittent

b) Accelerator

Acceleration:

G

❏ continuous / ❏ intermittent

c) Vehicle speed

km/h

MPH

❏ Advancing

❏ When accelerating

❏ When decelerating

❏ At low speed

❏ When turning

❏ Others:

d) Tire inflation pressure

Front RH tire:

kPa

Front LH tire:

kPa

Rear RH tire:

kPa

Rear LH tire:

kPa

e) Degree of wear

Front RH tire:

Front LH tire:

Rear RH tire:

Rear LH tire:

f) Steering wheel

❏ Sharp turning

❏ Gentle turning

❏ Straight forward motion

❏ Gentle return

❏ Sharp return

g) Tire/Wheel size

❏ Specified size

❏ Except specification (

)

h) Tire variation

❏ Summer tire

❏Studless tire (Brand:

)

i) Tire chains are fitted: 

❏ Yes / ❏ No

j) T-type tire is used: 

❏ Yes / ❏ No

k) Condition of suspension alignment:

l) Loading state:

m) Repair parts are used: 

❏ Yes / ❏ No

• Contents:
n) Others:

VDC(diag)-8

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

General Description

3. General Description

A: CAUTION

1. SUPPLEMENTAL RESTRAINT SYSTEM 
“AIRBAG”

Airbag system wiring harness is routed near the
ABS wheel speed sensor and VDCCM&H/U.

CAUTION:
• All airbag system wiring harness and con-
nectors are colored yellow. Do not use the elec-
trical test equipment on these circuits.
• Be careful not to damage the airbag system
wiring harness when servicing the ABS wheel
speed sensor and VDCCM&H/U.

B: INSPECTION

Before performing diagnosis, check the following
items which might affect VDC problems.

1. BATTERY

Measure the battery voltage and check electrolyte.

Standard voltage: 12 V or more

Specific gravity: 1.260 or more

2. GROUND

Check the tightening torque of ground (GB-7) bolt
of VDC.

Tightening torque:

13 N

⋅

m (1.3 kgf-m, 9.6 ft-lb)

3. BRAKE FLUID

1) Check the brake fluid level.
2) Check the brake fluid for leaks.

4. HYDRAULIC UNIT

Check the hydraulic unit.
• With brake tester <Ref. to VDC-8, CHECKING
THE HYDRAULIC UNIT ABS OPERATION WITH
BRAKE TESTER, INSPECTION, VDC Control
Module and Hydraulic Control Unit (VDCCM&H/
U).>
• Without brake tester <Ref. to VDC-8, CHECK-
ING THE HYDRAULIC UNIT ABS OPERATION
BY PRESSURE GAUGE, INSPECTION, VDC
Control Module and Hydraulic Control Unit (VDC-
CM&H/U).>

5. BRAKE DRAG

Check for brake drag.

6. BRAKE PAD AND ROTOR

Check the brake pad and rotor.
• FRONT <Ref. to BR-18, INSPECTION, Front
Brake Pad.> <Ref. to BR-19, INSPECTION, Front
Disc Rotor.>
• REAR <Ref. to BR-25, INSPECTION, Rear
Brake Pad.> <Ref. to BR-26, INSPECTION, Rear
Disc Rotor.>

7. TIRE

Check the tire specifications, tire wear and air pres-
sure. <Ref. to WT-2, SPECIFICATION, General
Description.>