pedal SUBARU LEGACY 1997 Service Repair Manual

BRAKES
IM13-21
4-4
13
.
Anti-lock
Brake
System
(ABS)
[5
.3i
Type]

2
.
FUNCTIONS
OF
SENSORS
AND
ACTUATORS

Name
Function

ABS
control
moduleand
hydraulic
ABSCM-
e
Calculates
and
determine
the
conditionsof
the
wheels
and
body
from
control
unit
(ABSCM&H/U)
section
the
wheel
speedsand
makes
a
proper
decision
suitable
for
the
current
situation
to
control
the
hydraulic
unit
.

In
the
ABS
operation
mode,
the
module
outputs
a
cooperative
control
signal
to
the
AT
control
module
.
(AT
vehicles
only)

Whenever
the
ignition
switch
is
placed
at
ON,
the
module
makes
a
self
diagnosis
.
When
anything
wrong
is
detected,
the
module
cuts
off
the
system
.

Communicates
with
the
Subaru
select
monitor
.

H/U-section
In
the
ABS
operation
mode,
the
H/U
changes
fluid
passages
to
control

the
fluid
pressure
of
the
wheel
cylinders
in
response
to
an
instruction
from
the
ABSCM
.

The
H/U
also
constitutes
thebrake
fluid
passage
from
the
master
cylin-
der
to
the
wheel
cylinders
together
with
pipings
.

Valve
relay-
Serves
asa
power
switch
for
the
solenoid
valve
and
motor
relay
coil
in
section
response
to
an
instruction
from
the
ABSCM
.

Motor
relay-
Serves
as
a
power
switch
for
the
pump
motor
in
response
to
an
instruc-
section
tion
from
the
ABSCM
.

Wheel
speed
sensor
(ABS
sensor)
Detects
the
wheel
speed
in
terms
of
a
change
in
the
magnetic
flux
den-
sity
passingthrough
the
sensor,
converts
it
into
an
electrical
signal,
and
outputs
the
electrical
signal
to
the
ABSCM
.

Tone
wheel
Gives
a
change
in
the
magnetic
flux
density
by
the
teeth
around
the
tone
wheel
to
let
the
ABS
sensor
generate
an
electrical
signal
.

G
sensor
(AWD
vehicle
only)
Detects
a
change
in
G
in
the
longitudinal
direction
of
the
vehicle
and
outputs
it
to
the
ABSCM
in
terms
of
a
change
in
voltage
.

Stop
light
switch
Transmits
the
information
on
whether
the
brakepedal
is
depressed
or
not
to
the
ABSCM
for
use
as
a
condition
in
determining
ABS
operation
.

ABS
warning
light
Alerts
the
driver
to
an
ABS
fault
.
When
the
diagnosis
connector
and
diagnosis
terminal
are
connected,
the
light
flashes
to
indicate
a
trouble
codes
in
response
to
an
instruction
from
the
ABSCM
.

AT
control
module
(TCM)
(AT
vehicles
only)
Provides
shift
controls
(fixing
the
speed
at
3rd
or
changing
front
and
rear
wheel
transmission
characteristics
on
4WD
vehicle)
in
response
to
an
instruction
fromthe
ABSCM
.

BRAKES
[M13-5]
4-413
.
Anti-lock
Brake
System
(AB
S)
[
5
.3i
Typ
e]

"
HYDRAULIC
CONTROL
UNIT
SECTION
(H/U)

The
H/U
is
a
fluid
pressure
controller
comprising
a
motor,
solenoid
valve,
housing,
relay,
etc
.
It

constitutes
two
diagonally
independent
brake
fluid
circuits
for
a
cross
piping
vehicle
.

"
The
pump
motor
rotates
an
eccentric
cam
to
let
the
plunger
pump
generatea
hydraulicpres-

sure
.

"
The
housing
accommodates
the
pump
motor,
solenoid
valve,
reservoir,
etc
.,
and
also
consti-
tutes
abrake
fluid
passage
.

"
The
plunger
pump
is
a
hydraulic
pump
which
drains
off
the
brake
fluid
which,
when
the
pressure

is
reduced,
is
discharged
to
the
reservoir,
and
sends
it
toward
the
master
cylinder
.

"
The
solenoid
valve
is
a
2-position
type
solenoidvalve
which
switches
the
brake
fluid
passages

between
the
wheel
and
master
cylinder
and
reservoir
sides
in
response
to
an
instruction
from
the

ABSCM
.

For
each
wheel
cylinder,
a
pairof
normally-closed
and
-opened
solenoid
valves
are
provided
.

*
The
inlet
solenoid
valve
is
duty-controlled
to
reduce
brake
fluid
pulsation
for
IowerABS
operation

noise
.

"
The
reservoir
is
a
fluid
chamber
which
temporarily
storesthe
brake
fluid
to
be
discharged
from

the
wheel
cylinder
when
the
pressure
is
reduced
.

"
The
damper
chamber
suppresses
thepulsation
of
the
brake
fluid
which,
when
the
pressure
is

reduced,
is
discharged
from
the
plunger
pump,
thereby
minimizing
the
kickbacks
to
the
brake

pedal
.

*
The
valve
relay
controls
the
solenoid
valve
and
motor
relay
energizing
power
supply
in
response

to
an
instruction
from
the
ABSCM
.
In
normal
(1G
ON)
condition,
the
relay
is
actuated
to
supply

power
to
the
solenoid
valve
and
motor
relay
.
When
an
error
occurs
in
the
system,
the
valve
relay

is
forced
to
OFF
to
keep
the
fluid
pressure
circuit
in
the
normal
mode
(normal
brake
mode)
and

also
constitute
the
ABS
warning
light
operating
circuit
.

"
The
motor
relay
supplies
power
to
the
pump
motor
to
operate
the
plunger
pump
in
response
to

an
instruction
from
the
ABSCM
in
the
ABS
control
mode
.

TheH/U
has
four
operating
modes
;
normal
mode
(control
OFF
:
normalbrake
mode),
"increase",

"hold"
and
"decrease"
modes
(control
ON
in
all
the
three
modes)
.

7

SERVICE
PROCEDURE
[w2scI]
4-4

25
.
ABS
Control
Module
and
Hydraulic
Control
Unit
(ABSCM&H/U)
[ABS
5
.3i
Type]

4)
Bleed
air
from
the
pressure
gauges
.

5)
Perform
ABS
sequence
control
.

Ref
.
to
[W25D0]
.*10
>

6)
When
thehydraulic
unit
begins
to
work,
and
first
the

FL
side
performs
decompression,
holding,
and

compression,
and
then
the
FR
side
performs

decompression,
holding,
and
compression
.

7)
Read
values
indicated
on
the
pressure
gauge
and

check
if
the
fluctuationof
the
values
between
decompres-

sion
and
compression
meets
the
standard
values
.
Also

check
if
any
irregular
brake
pedal
tightness
is
felt
.

Initial
value
When
decompressed
When
compressed

Front
wheel
3,432
kPa
(35
kg/cmz,
498
psi)
490kPa
(5
kg/cm2,
71
psi)
3,432
kPa
(35
kg/cm2,
498
psi)

or
less
or
more

Rear
wheel
3,432
kPa
(35
kg/cm2,
498
psi)
490kPa
(5
kg
/cm2,
71
psi)
3,432
kPa
(35
kg/cm2,
498
psi)

or
less
or
more

8)
Remove
pressure
gauges
from
FL
and
FR
caliper
bod-

ies
.

9)
Remove
air
bleeder
screws
from
the
RL
andRR
caliper

bodies
.

10)
Connect
the
air
bleeder
screws
to
the
FL
and
FR
cal-

iper
bodies
.

11)
Connect
two
pressure
gauges
to
the
RL
and
RR
cal-
iper
bodies
.

12)
Bleed
air
from
the
pressure
gauges
and
the
FL
and

FR
caliper
bodies
.

13)
Perform
ABS
sequence
control
.

<
Ref
.
to
[W25D0]
.*10
>

14)
When
thehydraulic
unit
begins
to
work,
at
first
the
RR

side
performs
decompression,
holding,
and
compression,

and
then
the
RL
side
performs
decompression,
holding,

and
compression
.

15)
Read
values
indicated
on
the
pressure
gauges
and

check
if
they
meet
thestandardvalue
.

16)
After
checking,
remove
the
pressure
gauges
from
cal-

iper
bodies
.

17)
Connect
the
air
bleeder
screws
to
RL
and
RR
caliper

bodies
.

18)
Bleed
air
from
brake
line
.

9

4-4
[wzsc2]
SERVICE
PROCEDURE

25
.
ABS
Control
Module
and
Hydraulic
Control
Unit
(ABSCM&H/U)
(ABS
5
.3i
Type]

{~~Y+)~

_~00

G4M0464

2
.
CHECKINGTHE
HYDRAULIC
UNIT
ABS
OPERATION

WITH
BRAKE
TESTER

1)
In
the
case
of
AWD
AT
vehicles,
install
aspare
fuse
with

the
FWD
connector
in
the
engine
compartment
to
simu-

late
FWD
vehicles
.

2)
Prepare
for
operating
ABS
sequence
control
.
<
Ref,to

[W25D1
]*10
or
[W25D2]
.*10
>

3)
Setthe
front
wheels
orrear
wheels
on
the
brake
tester

and
set
the
select
lever's
position
at
"neutral"
.

4)
Operate
the
brake
tester
.

5)
Perform
ABS
sequence
control
.
<
Ref
.
to
[W25D1]*10

step
1
or
[W25D2]*10
step
1
.
>

6)
Hydraulic
unit
begins
to
work
;
and
check
the
following

working
sequence
.

(1)
The
FL
wheel
performs
decompression,
holding,

and
compression
in
sequence,
and
subsequently
the

FR
wheel
repeats
the
cycle
.

(2)
The
RR
wheel
performs
decompression,
holding,

and
compression
in
sequence,
and
subsequently
the

RL
wheel
repeats
the
cycle
.

7)
Read
values
indicated
on
the
brake
tester
and
check

if
the
fluctuationof
values,
when
decompressed
and

compressed,
meet
the
standard
values
.

Unit
:
N
(kg,
Ib)

Initial
value
When
decompressed
When
compressed

Front
wheel
981
(100,
221)
490
(50,
110)or
less
981
(100,
221)
or
more

Rear
wheel
981
(100,
221)
490
(50,
110)
or
less
981
(100,
221)or
more

8)
After
checking,
also
check
if
any
irregular
brake
pedal

tightness
is
felt
.

10

SERVICE
PROCEDURE
[W25D21
4-4

25
.
ABS
Control
Module
and
Hydraulic
Control
Unit
(ABSCM&H/U)
[ABS
5
.3i
Type]

Diagnosis
connector
--J

1

I`

--~
~
''-
Diagnosis
terminals

3
terminal
6
terminal
-
/

B4M0082D
D
:
ABS
SEQUENCE
CONTROL

1)
Under
the
ABS
sequence
control,
after
thehydraulic

unit
solenoid
valve
is
driven,
theoperation
of
thehydrau-

lic
unit
can
be
checked
by
means
of
the
brake
tester
or

pressure
gauge
.

2)
ABS
sequence
control
can
be
started
by
diagnosis

connector
or
select
monitor
.

1
.
OPERATIONAL
GUIDELINES
OF
THE
ABS

SEQUENCE
CONTROL
WITH
DIAGNOSIS
CONNECTOR

1)
Connect
diagnosis
terminals
to
terminals
No
.
3
andNo
.

6
of
the
diagnosis
connector
beside
driver's
seat
heater

unit
.

2)
Setthe
speed
of
all
wheels
at
4
km/h
(2
MPH)
or
less
.

3)
Turn
ignition
switch
OFF
.

4)
Within
0
.5
seconds
after
the
ABS
warning
light
goes

out,
depress
the
brake
pedal
and
hold
it
immediately
after

ignition
switch
is
turned
to
ON
.

CAUTION
:

Do
not
depress
the
clutch
pedal
.

NOTE
:

*
When
the
ignition
switch
is
setto
on,the
brake
pedal

must
not
be
depressed
.

Engine
must
not
operate
.

5)
After
completion
of
ABS
sequence
control,
turn
ignition

switch
OFF
.

2
.
OPERATIONAL
GUIDELINES
OF
THE
ABS

SEQUENCE
CONTROL
WITH
SELECT
MONITOR

NOTE
:

In
the
event
of
any
trouble,
the
sequence
control
may
not

be
operative
.
In
such
a
case,
activate
the
sequence

control,
referring
to
"OPERATIONAL
GUIDELINES
OF
THE

ABS
SEQUENCE
CONTROL
WITHDIAGNOSIS
CONNEC-

TOR
"
.
<
Ref
.
to
4-4
[W25D1],*10>

1)
Connect
select
monitor
to
data
link
connector
beside

driver's
seat
heater
unit
.

2)
Turn
ignition
switch
ON
.

3)
Put
select
monitor
to
ABS
mode
.

11

4-4
[W25D2]
SERVICE
PROCEDURE

25
.
ABS
Control
Module
and
Hydraulic
Control
Unit
(ABSCM&H/U)
[ABS
5
.3i
Type]

[F-101
O
ENT

B4M0635

ABS
FUNCTION

CHECK
MODE

B4M0997
I

BRAKE
ON

KEEP100-150

B4M0998
I

MODE
START
PRESS
ENT
KEY

B4M0999

FUNCTION
START

UNABLE

SWIM

4)
Press
FD
1
ENT
key
.

5)
The
message
shown
in
the
figure
is
displayed
.

6)
The
message
shown
in
the
figure
is
displayed
as
fol-

lows
:

(1)
When
using
the
brake
tester,
depress
brake
pedal

with
braking
force
of
981
N
(100
kg,
221
Ib)
.

(2)
When
using
the
pressure
gauge,
depress
brake

pedalsoas
to
make
the
pressure
gauge
indicate
3,432

kPa
(35
kg/cm2,
498
psi)
.

CAUTION
:

Do
not
depress
the
clutch
pedal
.

7)
When
the
message
shown
in
the
figure
is
displayed,

press
ENT
key
.

8)
Check
points
will
be
displayed
on
select
monitor
.

9)
WhenABS
sequence
control
cannot
be
started
(by

system
malfunction,
etc
.),
the
message
shown
in
the
fig-

ure
will
be
displayed
.

NOTE
:

Read
the
trouble
codes
.
Repair
faulty
parts
.

12

SERVICE
PROCEDURE
[w2sDa1
4-4

25
.
AgS
Control
Module
and
Hydraulic
Control
Unit
(ABSCM&H/U)
[ABS
5
.3i
Type]

AB
S
FUNCTION

CHECK
END

B4M1030

MODE
RESTART?

0
:
YE
S
1
:
NO

H4M
1144

10)
After
completion
of
ABS
sequence
control
.

11)
Press0key
tostart
ABS
sequence
control
again
and

press
1
key
to
end
.

3
.
CONDITIONS
FOR
COMPLETIONOF
ABS

SEQUENCE
CONTROL

When
the
following
conditions
develop,
the
ABS
sequence

control
stops
and
ABS
operation
is
returned
to
the
normal

control
mode
.

1)
When
the
speed
ofat
least
one
wheel
reaches
10
km/h

(6
MPH)
.

2)
When
terminal
No
.
3
or
No
.
6
are
separated
from
diag-

nosis
terminals
.
(When
select
monitor
is
not
used
.)

3)
When
the
brakepedal
is
released
during
sequence

control
and
the
braking
lamp
switch
is
set
to
off
.

4)
When
brake
pedal
is
depressed
afterignition
key
is

turned
to
ON,
and
before
ABS
warning
light
goes
out
.

(When
select
monitor
is
not
used
.)

5)
When
brakepedal
is
not
depressed
after
ignition
key

is
turned
to
ON,
acrd
within
0
.5
seconds
after
ABS
warn-

ing
light
goes
out
.
(When
select
monitor
is
not
used
.)

6)
After
completion
of
the
sequence
control
.

7)
When
malfunction
is
detected
.
(When
select
monitor
is

used
.)

13

4-4d
[TSBO]
BRAKES
[ABS
5
.31
TYPE]

6
.
Diagnostics
Chart
for
On-board
Diagnosis
System

B
:
CHECK
LIST
FOR
INTERVIEW

Check
the
following
items
about
the
vehicle's
state
.

1
.
THE
STATE
OF
THE
ABS
WARNING
LIGHT

ABS
warning
light
O
Always

comes
on
.
D
Sometimes

O
Onlyonce

O
Does
not
come
on
o
When
/how
long
does
it
come
on?
:

Ignition
key
position
O
LOCK

D
ACC

OON
(before
starting
engine)

D
START

O
On
afterstarting
(Engine
is
running)

O
On
after
starting
(Engine
is
stop)

Timing
O
Immediately
afterignition
is
ON
.
O
Immediately
after
ignition
starts
.

O
When
advancing
km/h
to
km/h

MPH
to
MPH

D
While
traveling
at
a
constant
speed
km/h
MPH

D
When
decelerating
km/h
to
km/h

MPH
to
MPH
OWhen
turning
to
right
Steering
angle
:
deg

Steering
time
:
sec

D
When
turning
to
left
Steering
angle
:
deg

Steering
time
:
sec

D
When
moving
other
electrical
parts
Parts
name
Operating
condition

2
.
SYMPTOMS

ABS
operating
D
Performsno
work
.

condition
D
Operates
only
when
abruptly
applying
brakes
.
Vehicle
speed
:
km/h

MPH

~
How
to
step
on
brake
pedal

a)
Operating
time
:
sec

b)
Operating
noise
:
O
Produce
/
D
Does
not
produce

oWhat
kind
of
noise?
O
Knock

O
Gong
gong

D
Bong

a
Buzz

D
Gong
gong
buzz

O
Others

c)
Reaction
force
of
brake
pedal

O
Stick
O
Press
down
once
with
a
clunk

O
Press
and
released

D
Others

12

BRAKES
[ABS
5
.31
TYPE]
[MO]
4-4d

6
.
DiagnosticsChart
for
On-board
Diagnosis
System

Behavior
of
vehicle
a)
Directional
stability
cannotbe
obtained
or
steering
arm
refuses
to
work
when
applying
brakes

O
Yes
/
ONo

When
:
D
Vehicle
turns
to
right

o
Vehicle
turns
to
left

D
Spins

D
Others

b)
Directional
stability
cannot
be
obtained
orsteering
arm
refuses
to
work
when
accelerating

O
Yes
/
O
No

When
:
O
Vehicle
turns
to
right

O
Vehicle
turns
to
left

D
Spins

O
Others

c)
Brakes
areout
of
order
:
O
Yes
/
ONo

What
:
O
Braking
distance
is
long

O
Brakes
lockor
drag

D
Pedal
stroke
is
long

D
Pedal
sticks

O
Others

d)
Poor
acceleration
:
D
Yes
/
ONo

What
:
D
Fails
to
accelerate

o
Engine
stalls

o
Others

e)
Occurrence
of
vibration
:
D
Yes
/
[]No

Where
What
kind

f)
Occurrence
of
abnormal
noise
:
O
Yes
/
DNo

Where

What
kind

g)
Occurrence
of
other
phenomena
:
D
Yes
/
ONo

What
kind
3
.
CONDITIONS
UNDER
WHICH
TROUBLE
OCCURS

Environment
a)
Weather
D
Fine

O
Cloudy

O
Rainy

D
Snowy

O
Various/Others

b)
Ambient
temperature
F(°C)

c)
Road
D
Urban
area

D
Suburbs

O
Highway

O
General
road

D
Ascending
slope

O
Descending
slope

O
Paved
road

O
Gavel
road

O
Muddy
road

O
Sandy
place

Cl
Others

d)
Road
surface
D
Dry

D
Wet

O
New-fallen
snow

O
Compressed
snow

O
Frozen
slope

O
Others

13

BRAKES
[ABS
5
.31
TYPE]
[T8X5]
4-4d

8
.
Diagnostics
Chart
with
Trouble
Code
by
ABS
Warning
Light

8X1
I
CHECK
STOP
LIGHTS
COME
ON
.

Depress
the
brake
pedal
.

CHECK
:
Do
stop
lights
come
on?

,rES
:
Go
to
step
8X2
.

No
:
Repair
stop
lights
circuit
.
I
$X2
I
CHECK
OPEN
CIRCUIT
IN
HARNESS
.

1)
Turn
ignition
switch
to
OFF
.

2)
Disconnect
connector
from
ABSCM&H/U
.

3)
Depress
brake
pedal

4)
Measure
voltage
between
ABSCM&H/U
connector
and

chassis
ground
.

Connector
&
terminal

(F49)
No
.
2
(+)
-
Chassis
ground
(-)
;

CHECK
:
Is
thevoltage
between
10
V
and
15
V?

YES
:
Go
to
step
8X3
.

No
:
Repair
harness
between
stop
light
switch
and

ABSCM&H/U
.

8X3
I
CHECK
POOR
CONTACT
IN
CONNECTORS
.

CHECK
:
Is
there
poor
contact
in
connector
between

stop
light
switch
and
ABSCM&HlU?
<
Ref
.
to

FOREWORD
[T3C1]
.*70
>

,rES
:
Repair
connector
.

No
:
Go
to
step
8X4
.

18X4
I
CHECK
ABSCM&H/U
.

1)
Connect
all
connectors
.

2)
Erase
the
memory
.

3)
Perform
inspection
mode
.

4)
Read
outthe
trouble
code
.

CHECK
:
Is
the
same
trouble
code
as
in
thecurrent

diagnosis
still
being
output?

,rES
:
Replace
ABSCM&H/U
.

No
:
Go
to
step
8X5
.

8X5
CHECK
ANY
OTHER
TROUBLE
CODES

APPEARANCE
.

CHECK
:
Are
other
trouble
codes
being
output?

Proceed
with
the
diagnosis
corresponding
to
the
trouble
code
.

No
:
A
temporary
poor
contact
.

83