Subaru Legacy III (2000-2003 year). Service manual — part 697

ABS-6

ABS (DIAGNOSTICS)

CHECK LIST FOR INTERVIEW

2. SYMPTOMS

ABS operating condi-
tion

❏

Performs no work.

❏

Operates only when abruptly applying brakes.

Vehicle speed :

km/h

MPH

• How to step on brake pedal :

a) Operating time :

sec

b) Operating noise :

❏

Produce /

❏

Does not produce

• What kind of noise?

❏

Knock

❏

Gong gong

❏

Bong

❏

Buzz

❏

Gong gong buzz

❏

Others :

c) Reaction force of brake pedal

❏

Stick

❏

Press down once with a clunk

❏

Press and released

❏

Others :

Behavior of vehicle

a) Directional stability cannot be obtained or steering arm refuses to work when applying brakes :

❏

Yes /

❏

No

• When :

❏

Vehicle turns to right

❏

Vehicle turns to left

❏

Spins

❏

Others :

b) Directional stability cannot be obtained or steering arm refuses to work when accelerating :

❏

Yes /

❏

No

• When :

❏

Vehicle turns to right

❏

Vehicle turns to left

❏

Spins

❏

Others :

c) Brakes are out of order :

❏

Yes /

❏

No

• What :

❏

Braking distance is long

❏

Brakes lock or drag

❏

Pedal stroke is long

❏

Pedal sticks

❏

Others :

d) Poor acceleration :

❏

Yes /

❏

No

• What :

❏

Fails to accelerate

❏

Engine stalls

❏

Others :

e) Occurrence of vibration :

❏

Yes /

❏

No

• Where
• What kind :

f) Occurrence of abnormal noise :

❏

Yes /

❏

No

• Where
• What kind :

g) Occurrence of other phenomena :

❏

Yes /

❏

No

• What kind :

ABS-7

ABS (DIAGNOSTICS)

CHECK LIST FOR INTERVIEW

3. CONDITIONS UNDER WHICH TROUBLE OCCURS

Environment

a) Weather

❏

Fine

❏

Cloudy

❏

Rainy

❏

Snowy

❏

Various/Others :

b) Ambient temperature

°

F (

°

C)

c) Road

❏

Urban area

❏

Suburbs

❏

Highway

❏

General road

❏

Ascending slope

❏

Descending slope

❏

Paved road

❏

Gravel road

❏

Muddy road

❏

Sandy place

❏

Others :

d) Road surface

❏

Dry

❏

Wet

❏

New-fallen snow

❏

Compressed snow

❏

Frozen slope

❏

Others :

Condition

a) Brakes

Deceleration :

g

❏

Continuous /

❏

Intermittent

b) Accelerator

Acceleration :

g

❏

Continuous /

❏

Intermittent

c) Vehicle speed

km/h

MPH

❏

Advancing

❏

Accelerating

❏

Reducing speed

❏

Low speed

❏

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) Genuine parts are used. :

❏

Yes /

❏

No

g) Chain is passed around tires. :

❏

Yes /

❏

No

h) T tire is used. :

❏

Yes /

❏

No

i) Condition of suspension alignment :

j) Loading state :

k) Repair parts are used. :

❏

Yes /

❏

No

• What :

l) Others :

ABS-8

ABS (DIAGNOSTICS)

GENERAL DESCRIPTION

3. General Description

A: CAUTION

1. SUPPLEMENTAL RESTRAINT SYSTEM
“AIRBAG”

Airbag system wiring harness is routed near the
ABS sensor, ABS control module and hydraulic
control unit.

CAUTION:
• All airbag system wiring harness and con-
nectors are colored yellow. Do not use electri-
cal test equipment on these circuit.
• Be careful not to damage airbag system wir-
ing harness when servicing the ABS sensor,
ABS control module and hydraulic control unit.

B: INSPECTION

Before performing diagnostics, check the following
items which might affect ABS problems:

1. BATTERY

Measure battery voltage and specific gravity of
electrolyte.

Standard voltage: 12 V, or more

Specific gravity: Above 1.260

2. BRAKE FLUID

1) Check brake fluid level.
2) Check brake fluid leakage.

3. HYDRAULIC UNIT

Check the hydraulic unit.
• 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).>
• Without brake tester <Ref. to ABS-7, CHECK-
ING THE HYDRAULIC UNIT ABS OPERATION
BY PRESSURE GAUGE, INSPECTION, ABS
Control Module and Hydraulic Control Unit (AB-
SCM&H/U).>

4. BRAKE DRAG

Check brake drag.

5. BRAKE PAD AND ROTOR

Check brake pad and rotor.
• Front <Ref. to BR-21, INSPECTION, Front
Brake Pad.> and <Ref. to BR-22, INSPECTION,
Front Disc Rotor.>
• Rear <Ref. to BR-26, INSPECTION, Rear Brake
Pad.> and <Ref. to BR-27, INSPECTION, Rear
Disc Rotor.>

6. TIRE

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

ABS-9

ABS (DIAGNOSTICS)

GENERAL DESCRIPTION

C: PREPARATION TOOL

1. SPECIAL TOOLS

2. GENERAL PURPOSE TOOLS

ILLUSTRATION

TOOL NUMBER

DESCRIPTION

REMARKS

24082AA210

CARTRIDGE

Troubleshooting for electrical systems.

22771AA030

SELECT MONITOR
KIT

Troubleshooting for electrical systems.
• 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 ampere.

Oscilloscope

Used for measuring sensor.

ST24082AA210

ST22771AA030