Subaru Legacy III (2000-2003 year). 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