Subaru Legacy IV (2008 year). Manual - part 899

ABS-12

ABS Sequence Control

ABS

NOTE:
The control operation starts from point A.

B: SPECIFICATION

1. CONDITIONS FOR COMPLETION OF 
ABS SEQUENCE CONTROL

When the following conditions develop, the ABS
sequence control stops and ABS operation is re-
turned to the normal control mode.
1) When the speed of at least one wheel reaches
10 km/h (6 MPH).
2) When the brake pedal is released during ABS
sequence control and the stop light switch is be-
comes OFF.
3) After completion of ABS sequence control.
4) When a malfunction is detected.

(1)

All wheel speed

(11)

RR compression valve

(20)

0.6 sec.

(2)

Ignition key

(12)

RL decompression valve

(21)

0.4 sec.

(3)

ABS warning light

(13)

RL compression valve

(22)

Point A

(4)

Stop light switch

(14)

Pump motor

(23)

Reset

(5)

Valve relay

(15)

1.5 sec.

(24)

Master cylinder pressure

(6)

FL decompression valve

(16)

Light OFF

(25)

FL wheel cylinder pressure

(7)

FL compression valve

(17)

Light ON

(26)

FR wheel cylinder pressure

(8)

FR decompression valve

(18)

1.0 sec.

(27)

RR wheel cylinder pressure

(9)

FR compression valve

(19)

1.4 sec.

(28)

RL wheel cylinder pressure

(10)

RR decompression valve

 

 

ABS-13

Front ABS Wheel Speed Sensor

ABS

4. Front ABS Wheel Speed 

Sensor

A: REMOVAL

1) Disconnect the ground cable from the battery.
2) Disconnect the ABS wheel speed sensor con-
nector located next to the front strut mounting
house in the engine compartment.
3) Remove the sensor harness bracket.

4) Remove the bolts which secure the sensor har-
ness to the front strut.
5) Remove the front ABS wheel speed sensor from
housing.

CAUTION:
• Be careful not to damage the sensor.
• Do not apply excessive force to the sensor
harness.

B: INSTALLATION

Install in the reverse order of removal.

Tightening torque:

Sensor:

7.5 N·m (0.76 kgf-m, 5.5 ft-lb)

Bracket:

33 N·m (3.3 kgf-m, 24 ft-lb)

CAUTION:
Be careful not to damage the sensor.

NOTE:
• Check the identification (mark) on the harness to
make sure there is no warpage. (RH: K1 (White),
LH: K2 (Yellow))
• Check if the harness is not pulled and does not
come in contact with the suspension or body during
steering wheel effort.

(1) To the front ABS wheel speed sensor connector

(2) Sensor harness bracket

ABS00386

(1)

(2)

ABS00387

ABS-14

Front ABS Wheel Speed Sensor

ABS

C: INSPECTION

1. CHECK WITH SUBARU SELECT MONITOR

1) Connect the Subaru Select Monitor to data link
connector.
2) Select {Current Data Display & Save}. Check if
the speed indicated on the display changes in the
same manner as the speedometer reading during
acceleration/deceleration when the steering wheel
is in the straight-ahead position.
3) If the speed indicated on the display does not
change, check the ABS wheel speed sensor. <Ref.
to ABS-14, ABS WHEEL SPEED SENSOR, IN-
SPECTION, Front ABS Wheel Speed Sensor.>

2. ABS WHEEL SPEED SENSOR

1) Check the tip of the ABS wheel speed sensor for
foreign particles or damage. If necessary, clean the
tip or replace the ABS wheel speed sensor.
2) Connect a 12 V power supply to No. 2 terminal of
sensor connector as shown in the figure, then at-
tach resistance to the No. 1 terminal. Rotate the
wheel at about 2.75 km/h (2 MPH), and measure
the voltage using an oscilloscope.

Standard value of output voltage:

0.7 — 1.4 V

NOTE:
Check the ABS wheel speed sensor cable for dis-
continuity. If necessary, replace with a new part.

(1) Oscilloscope

(2) ABS wheel speed sensor

ABS00388

(2)

(1)

100

1.4 V

0.7 V

12 V

2

1

1

2

ABS-15

Rear ABS Wheel Speed Sensor

ABS

5. Rear ABS Wheel Speed 

Sensor

A: REMOVAL

1) Disconnect the ground cable from the battery.
2) Disconnect the connector from the rear ABS
wheel speed sensor.

3) Remove the sensor harness bracket from the
rear arm.

4) Remove the rear ABS wheel speed sensor from
the rear arm.

CAUTION:
• Be careful not to damage the sensor.
• Do not apply excessive force to the sensor
harness.

B: INSTALLATION

Install in the reverse order of removal.

CAUTION:
Be careful not to damage the sensor.

Tightening torque:

Sensor:

7.5 N·m (0.76 kgf-m, 5.5 ft-lb)

Bracket:

33 N·m (3.3 kgf-m, 24 ft-lb)

NOTE:
Check the identification (mark) on the harness to
make sure there is no warpage. (RH: K5 (White),
LH: K6 (Yellow))

C: INSPECTION

1. ABS WHEEL SPEED SENSOR

<Ref. to ABS-14, ABS WHEEL SPEED SENSOR,
INSPECTION, Front ABS Wheel Speed Sensor.>

ABS00389

ABS00166

ABS00167

ABS00168

ABS00390