1996 SUBARU LEGACY wheel

B4M0494
2. FR.SS OR MV
—Irregular signals from front right ABS sensor in
decompressing mode—
DIAGNOSIS:

Faulty ABS sensor signal (noise, irregular signal, etc.)

Faulty hydraulic unit

Faulty harness/connector

Faulty ABS/TCS control module
TROUBLE SYMPTOM:

ABS does not operate.

TCS does not operate.
1. Check ABS sensor mechanical trouble.

OK
Not OK
Repair ABS sensor/tone wheel.
2. Check ground circuit of ABS/TCS control
module.

OK
Not OK
Repair harness/connector.
3. Check sources of signal noise.

OK
Not OK
Repair noise sources.
4. Check operation of hydraulic unit.

OK
Not OK
Replace hydraulic unit.
Replace ABS/TCS control module.




99
4-4bBRAKES
10. Diagnostic Chart with Select Monitor

B4M0495
3. FR.SS OVER
—Excessive speed of front right ABS sensor signal—
DIAGNOSIS:

Faulty ABS sensor signal (noise, irregular signal, etc.)

Faulty harness/connector

Faulty ABS/TCS control module
TROUBLE SYMPTOM:

ABS and TCS do not operate.
1. Check ABS sensor mechanical trouble.

OK
Not OK
Repair ABS sensor/tone wheel.
2. Check ground circuit of ABS/TCS control
module.

OK
Not OK
Repair harness/connector.
3. Check sources of signal noise.

OK
Not OK
Repair noise sources.
Replace ABS/TCS control module.



100
4-4bBRAKES
10. Diagnostic Chart with Select Monitor

11. General Diagnostics Table
: Primary expected causes: Secondary expected causes
Trouble conditions
SymptomsHydraulic
unit
Speed sensor
P valve
Master cylinder
Calipers and piston
Pad
Rotor
Hand brake
Piping
Mixture of air
Brake booster and check valve
Axle and wheel
Alignment
Play of pedal
Rough road surface
Semicylindrical road surface
Loose or worn suspension
Tire
Wrong connection and wiring
Stroke sensor Solenoid valve
Motor
Mount bush ABS function
Directional stability cannot be
obtained when braking.Vehicle turns to right or left. 
Vehicle spins.
Out-of-order brakesLong braking distance
 
Brakes lock.  
Brakes drag.
Long pedal stroke  
Abnormal vehicle pitching 
Unstable braking force. One-
side brake refuses to work. 
TCS function
When accelerating abruptly,
directional stability cannot be
obtained when traveling on a
slippery road surface.Vehicle moves unsteadily.
Handle refuses to work.
Handle loses control. 
Bad acceleration, engine stall-
ing (In addition to the causes
listed here, check the ECM
specifications.)Engine stalls. Engine speed
fails to increase.
Engine speed increases sud-
denly.
Vibration occurs and abnormal
noise is produced.

When applying brakes abruptly.

When accelerating abruptly.

When driving on a slippery
road surface.Brake pedal heavily vibrates
when applying brakes.
   
Loud hydraulic unit operating
noise
Noise is produced from front
of vehicle.
Noise is produced from rear of
vehicle.
NOTE:
This list includes no engine failure and transmission failure.
127
4-4bBRAKES
11. General Diagnostics Table

6. INSPECTOR
Before advancing the vehicle after the engine starts, drive
the pump motor and valve for a very short time to function-
ally check the ABS/TCS brakes. It is not abnormal if, at this
time, operating noises of the valve and motor are produced
or kickback of the brake pedal is felt when stepping on the
pedal.
7. WHEN ATTACHING CHAINS
It is sometimes a good idea to turn off the TCS for better
advancing and accelerating the vehicle.
8. WHEN A DRUM TESTER IS USED (SPEEDOMETER
TEST, EXHAUST GAS TEST, BRAKE TEST, ETC.)
Before performing tests, turn the TCS off by operating the
TCS OFF switch or disconnect the fuse of ECM input
power source to put the machine out of operation. If oper-
ating other parts to put the TCS in the fail state
intentionally, trouble code will be recorded. Make sure to
clear the memory. Also, in a 2-wheel tester, wheel speed
sensor failure can be detected, making the TCS fail. This
case is also not abnormal and clearing the memory is
required.
129
4-4bBRAKES
12. Phenomena Peculiar to the System

3. Electrical Components Location
B4M0782A
1Hydraulic control unit (H/U)

2Proportioning valve

3ABS control module (ABSCM)

4Diagnosis connector

5ABS warning light

6Data link connector (for Subaru select monitor)

7Transmission control module (only AT vehicle)
8Tone wheel

9ABS sensor

10Wheel cylinder

11G sensor (only AWD vehicle)

12Brake switch

13Master cylinder

14Relay box
4
4-4cBRAKES [ABS 5.3 TYPE]
3. Electrical Components Location

Contents Terminal No.Input/Output signal
Measured value and measuring conditions
ABS sensor
(Wheel
speed
sensor)Front left wheel 49—19
0.12—1V
(When it is 20 Hz.) Front right wheel 14—15
Rear left wheel 16—17
Rear right wheel 18—46
Hydraulic
control unitSolenoid
valveFront left outlet 51—1
10—13 V when the valve is OFF and
less than 1.5 V when the valve is ON. Front right outlet 3—1
Rear left outlet 4—1
Rear right outlet 50—1
Front left inlet 24—1
Front right inlet 30—1
Rear left inlet 31—1
Rear right inlet 23—1
Relay boxValve relay power supply 27—110—13 V when ignition switch is ON.
Valve relay coil 47—1 Less than 1.5 V when ignition switch is ON.
Motor relay coil 22—1More than 10 V when the ABS control does not operate still
and less than 1.5 V when ABS operates.
Motor monitoring 10—1Less than 1.5 V when the ABS control does not operate still
and more than 10 V when ABS operates.
G sensor
(AWD
model only)power supply 8—45 4.75—5.25 V
ground 45—
output 7—45 2.3±0.2 V when vehicle is in horizontal position.
Stop light switch 36—1Less than 1.5 V when the stop light is OFF and more than
4.5 V when the stop light is ON.
ABS warning light 54—1Less than 1.5 V during 1.5 seconds when ignition switch is
ON, and 10—14 V after 1.5 seconds.
AT ABS signal
(AT model only)12—1Less than 1.5 V when the ABS control does not operate still
and more than 5.5 V when ABS operates.
ABS operation signal monitor 39—1Less than 1.5 V when the ABS control does not operate still
and more than 5.5 V when ABS operates.
Select
monitorData is received. 11—1 Less than 1.5 V when no data is received.
Data is sent. 38—1 4.75—5.25 V when no data is sent.
Diagnosis
connectorTerminal No. 3 5—110—14 V when ignition switch is ON.
Terminal No. 6 13—110—14 V when ignition switch is ON.
Power supply 28—110—14 V when ignition switch is ON.
Grounding line 1—
Grounding line 55—
8
4-4cBRAKES [ABS 5.3 TYPE]
5. Control Module I/O Signal

B: CHECK LIST FOR INTERVIEW
Check the following items about the vehicle’s state.
1. THE STATE OF THE WARNING LIGHTS
a. ABS warning light

1Is always on.2Sometimes comes on.3Comes on only once.4Does not come on.
When/how long does it come on?
Ignition key
position
1Lock2Acc3On (before starting engine)4Start5On after starting (Engine: run)

6On after starting (Engine: stop)
Timing
1Immediately after ignition is on.2Immediately after ignition starts.

3When advancing (Speedmiles/h,miles/h)4While traveling at a constant speed (Speedmiles/h)

5When decelerating (Speedmiles/h,miles/h)

6When turning (To right, to left, steering angledeg., steering timesec)

7When moving other electrical parts (Part name:, Operating condition)
2. SYMPTOMS
ABS operating
condition1Performs no work.2Operates only when abruptly applying brakes. (Conditions: vehicle speedmiles/h, how
to step on brake pedal
)

3Operating time (sec., etc.)4Operating noise (Produced/Not produced)

5What kind of noise? (Knock, gong gong, bong, buzz, gong gong buzz, etc.)

6Reaction force of brake pedal (Stick, pressed down once with a clunk, pressed and released, etc.)
Behavior of
vehicle
1Directional stability cannot be obtained or steering arm refuses to work when applying brakes (vehicle turns to
right, turns to left, spins, etc.
).

2Directional stability cannot be obtained or steering arm refuses to work when accelerating (vehicle turns to right,
turns to left, spins, etc.
).

3Brakes are out of order (braking distance is long, brakes lock or drag, pedal stroke is long, pedal sticks, etc.
).

4Poor acceleration (fails to accelerate, engine stalls, etc.).

5Vibration, abnormal noise (operating noise is loud, noise is produced during operation from the front of vehicle
(right, left) (tones:
), noise is produced during operation from the rear of vehicle (tones:, others
)

6Other phenomena (concrete symptoms)
3. CONDITIONS UNDER WHICH TROUBLE OCCURS
Environment1Weather (fine, cloudy, rain, snow, etc.)

2Ambient temperature (°C/°F)

3Road (urban area, suburbs, highway, general road, ascending slope, descending slope, paved road, gravel road,
muddy road, sandy place, etc.
)

4Road surface (dry, wet, new-fallen snow, compressed snow, frozen slope, etc.)
Conditions
1Brakes (decelerationg, continuous/intermittent)2Accelerator (accelerationg, continuous/intermittent)

3Travel speed (miles, advancing, accelerating, reducing speed, low speed, turning, etc.)

4Condition of tire of each wheel (air pressure, degree of wear, whether or not genuine parts are used,
whether or not chain is passed around tires, whether or not T tire is used.) others (
)

5Condition of suspension alignment ()

6Loading state ()
4. REPAIRED PARTS ARE USED OR NOT
11
4-4cBRAKES [ABS 5.3 TYPE]
6. Diagnostics Chart for On-board Diagnosis System

8B5CHECK ABS SENSOR MECHANICAL
TROUBLE.
: Tightening torque:
32±10 N⋅m (3.3±1.0 kg-m, 24±7 ft-lb)
Are the ABS sensor installation bolts tight-
ened securely?
: Go to next.
: Tighten ABS sensor installation bolts securely.
: Tightening torque:
13±3 N⋅m (1.3±0.3 kg-m, 9±2.2 ft-lb)
Are the tone wheel installation bolts tight-
ened securely?
: Go to next step.
: Tighten tone wheel installation bolts securely.
G4M0700
1) Measure tone wheel-to-pole piece gap over entire
perimeter of the wheel.
: Is the gap within the specifications shown
in the following table?
SpecificationsFront wheel Rear wheel
0.9—1.4 mm
(0.035—0.055 in)0.7—1.2 mm
(0.028—0.047 in)
G4M0701
: Go to next step.
: Adjust the gap.
NOTE:
Adjust the gap using spacers (Part No. 26755AA000). If
spacers cannot correct the gap, replace worn sensor or
worn tone wheel.
2) Measure hub runout.
: Is the runout less than 0.05 mm (0.0020 in)?
: Go to step8B6.
: Repair hub.
32
4-4cBRAKES [ABS 5.3 TYPE]
8. Diagnostics Chart with Trouble Code