Subaru Legacy IV (2008 year). Manual - part 923

VDC(diag)-7

Check List for Interview

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

Condition

a) Brakes

Deceleration:

G

 Continuous / 

 Intermittent

b) Accelerator

Acceleration:

G

 Continuous / 

 Intermittent

c) Vehicle speed

km/h

MPH

 Advancing
 While accelerating
 While 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 chain is attached: 

 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

General Description

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

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 electri-
cal 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
THE BRAKE TESTER, INSPECTION, VDC Con-
trol Module and Hydraulic Control Unit (VDC-
CM&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-13, INSPECTION, Front Brake
Pad.> <Ref. to BR-14, INSPECTION, Front Disc
Rotor.>
• Rear <Ref. to BR-19, INSPECTION, Rear Brake
Pad.> <Ref. to BR-21, INSPECTION, Rear Disc
Rotor.>

7. TIRE

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

C: PREPARATION TOOL

1. SPECIAL TOOL

2. GENERAL TOOL

ILLUSTRATION

TOOL NUMBER

DESCRIPTION

REMARKS

1B022XU0

SUBARU SELECT 
MONITOR III KIT

Used for troubleshooting the electrical system.

TOOL NAME

REMARKS

Circuit tester

Used for measuring resistance, voltage and current.

Oscilloscope

Used for measuring the sensor.

ST1B022XU0

VDC(diag)-9

Electrical Component Location

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

4. Electrical Component Location

A: LOCATION

(1)

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

(5)

ABS warning light

(10)

Magnetic encoder

(6)

VDC indicator light

(11)

ABS wheel speed sensor

(2)

Connector

(7)

VDC warning light and VDC OFF 
indicator light

(12)

Yaw rate & lateral G sensor

(3)

Transmission control module (TCM)

(13)

Data link connector

(4)

Brake warning light (EBD warning 
light)

(8)

Steering angle sensor

(14)

Engine control module (ECM)

(9)

VDC OFF switch

(15)

Stop light switch

VDC00469

(4) (5) (6)

(7)

(8)

(1)

(2)

(3)

(15)

(14)

(12)

(13)

(11)

(10)

(11)

(10)

(9)

VDC(diag)-10

Electrical Component Location

VEHICLE DYNAMICS CONTROL (VDC) (DIAGNOSTICS)

VDC00455

(1)

VDC00656

(5)

(4)

(6)

(7)

(8)

VDC00235

VDC00234

(11)

(10)

(10)

VDC00456

(12)

VDC00242

(13)