relay SUBARU LEGACY 1997 Service Repair Manual

4-4
LM13-1]
BRAKES
13
.
Anti-lock
Brake
System
(ABS)
[5
.3i
Type]

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

1
.
FEATURE

*
This
ABS
5
.3i
type
incorporates
the
hydraulic
control
unit,
ABS
control
module,
valve
relay
and

motor
relay
in
one
unit
for
betterproductivity
and
lightweight
.

*
The
ABS
(Anti-lock
brake
system)
electrically
controls
brake
fluid
pressure
to
prevent
wheel

"lock"
during
braking
on
slippery
road
surfaces,
thereby
improving
directional/steering
stability
as

well
as
shortening
the
braking
distance
.

*
If
the
ABS
becomes
inoperative,
the
fail-safe
system
activates
to
ensure
it
acts
asa
conventional

brake
system
.
The
warning
light
also
comes
on
to
indicate
that
the
ABS
is
malfunctioning
.

"
The
front-and-rear
wheels
utilize
a
4-sensor,
4-channel
control
design
:
the
front
wheels
havean

independent
control
design*1
and
the
rear
wheels
have
a
select
low
control
design*2
.

*1
:
A
system
which
independently
controls
fluid
pressure
to
left
and
right
front
wheels
.

*2
:
A
system
which
provides
the
same
fluid
pressure
control
for
the
two
rear
wheels
if
either
wheel

starts
to"lock
."

10
ABS
control
moduleand
hydraulic
control
unit
(ABSCM&H/U)
Proportioning
valve
OO
Diagnosisconnector
OO
ABS
warning
light

OO
Data
link
connector
(for
SUBARU
select
monitor)
OO
Transmission
control
module
(only
AT
vehicle)
Tone
wheel

OO
ABS
sensor
09
Wheel
cylinder
O
G
sensor
(only
AWD
vehicle)
>>
Brake
switch
D
Master
cylinder

?15A

2

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
.

4-4
[M13-21
BRAKES

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

O

BATTERY

B4H1216A

O
ABS
control
module
and
S
Front
right
outlet
solenoidvalve
D
ABS
warning
light
hydraulic
control
unit
(2
Rear
left
inlet
solenoid
valve'
0
Stop
light
switch
9
ABS
control
module
section
D
Rear
left
outlet
solenoidvalve
0
Stop
light
Valve
relay
0
Rear
right
inlet
solenoidvalve
(5
G
sensor
(only
AWD
model)
O
Motor
relay
8
Rear
right
outlet
solenoid
valve
0
Front
left
ABS
sensor
m
Motor
R
Transmission
control
module
Z
Front
right
ABS
sensor
Front
left
inlet
solenoid
valve
(only
AT
module)
Z
Rear
left
ABS
sensor
8
Front
left
outlet
solenoidvalve
(3
Diagnosis
connector
(8
Rear
right
ABS
sensor
Front
right
inlet
solenoidvalve
0
Data
link
connector

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

4-4
[W25D4]
SERVICE
PROCEDURE

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

4
.
CONDITIONS
FORABS
SEQUENCE
CONTROL

4
km/h

Speed
of
all
wheels

HIGF
Terminal
No
.3
and
No
.6
LOV1
Operational
guide
lineofIgnition
key
switch
O
sequence
OFF

control
O
ABS
warning
light
OFF

HIGF
Stop
light
switch
LO"

HIGF
AT
ABS
signal
LOW

Valve
relay
ON

OFF

FL
outlet
valve
ON
OFF

FL
inlet
valve
O
NOFF

Operational
FR
outlet
valve
ON
OFF
pattern
of
ON
sequence
FR
inlet
valve
OFF
control
RR
outlet
valve
OFF
RR
inlet
valve
ON
OAF

RL
outlet
valve
OFF

RL
inlet
valve
ONOFF

Pump
motor
OFF

Operational
Pressure
of
master
cylinder

pressure
of
Pressure
of
FLwheel
cylinder
Pressure
of
FR
wheel
cylinder
sequence
Pressure
of
RR
wheel
cylinder
control
Pressure
of
RL
wheel
cylinder

Unit
:
second

B4M1001A
I

NOTE
:

*
When
select
monitor
is
used,
control
operation
starts
at

point
A
.
The
patterns
from
IGN
key
ON
to
the
point
A
show

that
operation
is
started
by
diagnosis
connector
.

HIGH
means
high
voltage
.

LOW
means
low
voltage
.

14

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

4
.
Schematic

4
.
Schematic

10

14

BATTERY
16

-----I

---
IGN

17
----I

=
O_
.__J

C5
19

U6

--
-
------
H
!
20

-----------
g

10

1
-
~
11

----------
----
r
12
23
`
"
...
.,`
@
.

Twisted
w
ire

B
4M1227A

ABS
control
module
and
hydraulic
control
unit

(ABSCM&H/U)

~2
ABS
control
module
area

~3
Valve
relay

~a
Motor
relay

~5
Motor

06
Front
left
inlet
solenoid
valve

07
Front
left
outlet
solenoid
valve

~8
Front
right
inlet
solenoid
valve

Front
right
outlet
solenoid
valve
~o
Rear
left
inlet
solenoid
valve

Rear
left
outlet
solenoid
valve

g
Rear
right
inlet
solenoid
valve

Rear
right
outlet
solenoid
valve

~a
Transmission
control
module
(only
AT
model)

~5
Diagnosis
connector

~s
Data
link
connector

ABS
warning
light

Qe
Stop
light
switch

Stop
light

~o
G
sensor
(only
AWD
model)

Front
left
ABS
sensor

~2
Front
right
ABS
sensor

Rear
left
ABS
sensor

Rear
right
ABS
sensor

6

BRAKES
[ABS
5
.31
TYPE]
'
[T501]
4-4d

5
.
Control
Module
I/O
Signal

Terminal

N
Input/Output
signal
Contents
o
.

_)
Measured
value
andmeasuring
conditions

ABS
Front
left
wheel
9-10

sensor'2
Front
right
wheel
11-12
0
.12
-
1
V
(Wheel

speed
Rear
left
wheel
7-8
(When
it
is
20Hz
.)

sensor)
Rear
right
wheel
14-15

Valve
relay
power
supply
24-23
10
-
15
Vwhen
ignition
switch
is
ON
.

Motor
relay
power
supply
25-23
10
-
15
Vwhen
ignition
switch
is
ON
.

G
sensor'2
Power
supply
30-28
4
.75
-
5
.25
V

(AWD
model
ground
28
-

only)
output
6-28
2
.3f0
.2
V
when
vehicle
isin
horizontal
position
.

Stop
light
switch*1
2-23
Less
than
1
.5
V
when
the
stop
light
is
OFF
and,10
-
15
V

when
thestop
light
is
ON
.

ABS
warning
light`2
21-23
Less
than
1.5
V
during
1
.5
seconds
when
ignition
switch
is

ON,and
10
-
15
V
after
1.5
seconds
.

AT
ABS
signal'2

(AT
model
only)
31-23
Less
than
1
.5
V
when
the
ABS
control
does
not
operate
still

and
more
than5
.5
V
when
ABS
operates
.

ABS
operation
signal
monitor*2
3--23
Less
than
1
.5
V
when
the
ABS
control
does
not
operate
still

and
more
than5
.5
V
when
ABS
operates
.

Select
Data
is
received
.
20-23
Less
than
1
.5
V
when
no
data
is
received
.

monitor'2
Data
is
sent
.
5--23
4
.75
-
5
.25
V
when
no
data
is
sent
.

ABS
Terminal
No
.
3
29-23
10
-
15
V
when
ignition
switch
is
ON
.
diagnosis

connector*2
Terminal
No
.
6
4-23
10
-
15
V
when
ignition
switch
is
ON
.

Power
supply'1
1-23
10
-
15
V
when
ignition
switch
is
ON
.

Grounding
line
23
-

Grounding
line
~26

*1
:
Measure
the
I/O
signal
voltage
after
removing
the
connector
from
the
ABSCM&H/U
terminal
.
'2
:
Measure
the
I/O
signal
voltage
at
connector
(F2)
or
(Fi)
.

9

4-4a
[TBAO1
BRAKES
[ABS
5
.31
TYPE]

8
.
Diagnostics
Chart
with
Trouble
Code
by
ABS
Warning
Light

8
.
Diagnostics
Chart
with
Trouble
Code

by
ABS
Warning
Light

A
:
LIST
OF
TROUBLE
CODE

Trouble
code
Contents
of
diagnosis
Ref
.
to
11

Start
code

e
Trouble
code
is
shown
afterstart
code
.

*
Only
start
code
is
shown
in
normal
condition
.

-

21
Front
right
ABS
sensor
[T8B0]*10

23
Abnormal
ABS
sensor
Front
left
ABS
sensor
[T8C0]*10

25
(Open
circuit
or
input
voltage
too
high)
Rear
right
ABS
sensor
[T8D0]*10

27
Rear
left
ABS
sensor
[T8E0]x10

22
Front
right
ABS
sensor
[T8F0]*10

24
Front
left
ABS
sensor
[T8G0]dr10

26
Abnormal
ABS
sensor

(Abnormal
ABS
sensor
signal)
Rear
right
ABS
sensor
[T8H0]*10

28
Rear
left
ABS
sensor
[T810]*10

29
Any
one
of
four
[T8J0]*10

31Front
rightinlet
valve
[T8K0]*10

32
Front
right
outlet
valve
[7800]*10

33
Front
left
inlet
valve
[TSLO]*10

34
Abnormal
solenoid
valve
circuit(s)
in
Front
left
outlet
valve
[T8PO]*10

35
ABS
control
module
and
hydraulic
unit
Rear
right
inlet
valve
[T8M0]*10

36Rear
right
outlet
valve
[T8QOj*10

37
Rear
left
inlet
valve
[T8N0]x10

38Rear
left
outlet
valve
[T8R0]*10

41
Abnormal
ABS
control
module
[T8SO1*10

42
Source
voltage
is
abnormal
.
[7870]*10

44
A
combination
of
AT
control
abnormal
[T8U0]t`r10

51
Abnormal
valve
relay
[T8V0]*10

52
Abnormal
motor
and/or
motor
relay
[T8W0]*10

54
Abnormal
stop
light
switch
(78X0]*10

56
Abnormal
G
sensor
output
voltage
[T8Y0)*10

30

4-4d
[TSVO1
BRAKES
[ABS
5
.31
TYPE]

8
.
Diagnostics
Chart
with
Trouble
Code
by
ABS
Warning
Light

V
:
TROUBLE
CODE
51

-
ABNORMAL
VALVERELAY
-

DIAGNOSIS
:

Faulty
valve
relay

TROUBLE
SYMPTOM
:

*
ABS
does
notoperate
.

WIRING
DIAGRAM
:

ABS
control
module
and
hydraulic
control
unit
Fuse
SBF-4

t

No
.
19

Valve
relay
~
F4
Lk
9

F2
8100
Fuse
IGN
sw
SBF-4
FL1.25B

Motor
~
O
No
.18
relay

r

w
m

Solenoid
valve

FL
inlet

FL
outlet

FR
inlet

FR
outlet

RL
inlet

RL
outlet

RR
inlet

RR
outlet

Pump
motor

M

E

100
f49

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~
~
q
27
12
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29
1
30
1
31
1

84M1253

74

BRAKES
[ABS
5
.31
TYPE]
IT8V3]4-4d

8
.
Diagnostics
Chad
with
Trouble
Codeby
ABS
Warning
Light

F49

1
1
213141516
1
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B4M1243A

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IIII
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84M1272A

18V-,
CHECK
INPUT
VOLTAGE
OF
ABSCM&H/U
.

1)
Turn
ignition
switch
to
OFF
.

2)
Disconnect
connector
from
ABSCM&H/U
.

3)
Run
the
engine
at
idle
.

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

chassis
ground
.

Connector
&
terminal

(F49)
No
.
1
(+)
-
Chassis
ground
(
)
:

(F49)
No
.
24
(+)
-
Chassis
ground
(
)
:

CHEGK
:
Is
the
voltage
between
10
V
and
15
V?

YES
:
Go
to
step
8V2
.

No
:
Repair
harness
connector
between
battery
and

ABSCM&H/U
.

8V2
I
CHECK
GROUND
CIRCUIT
Of
ABSCM&H/U
.

1)
Turn
ignition
switch
to
OFF
.

2)
Measure
resistance
between
ABSCM&H!U
connector

and
chassis
ground
.

Connector
&
terminal

(F49)
No
.
23
-
Chassis
ground
:

CHECK
:
Is
the
resistance
leis
than0
.5
0?

Go
to
step
8V3
.

No
:
Repair
ABSCM&H/U
ground
harness
.

8V3
CHECK
VALVE
.
RELAY
IN
ABSCM&H/U
.

Measure
resistance
between
ABS,CM&H/U
and
terminals
.

Terminals

No
.
23
(+)
-
-
No
.
24
(-)

CHECK
:
Is
theresistance
amore
than
1'
MSZ?

YES
:
Go
to
step
8V4
.

No
:
Replace
ABSCM&H/U
.

75