Control unit SUBARU LEGACY 1995 Service Owner's Manual

2. CONDITIONS FOR COMPLETION OF SEQUENCE
CONTROL
1) When the speed of at least one wheel reaches 10 km/h
(6 MPH), the operation is returned to the normal control
mode.
2) When L terminal is separated from ground, the opera-
tion is returned to the normal control mode.
3) When K terminal is separated from ground, the opera-
tion goes to the trouble code display mode.
4) When the brake pedal is released during sequence con-
trol and the braking lamp switch is set to off, the operation
is returned to the normal control mode.
5) After completion of the sequence control, the operation
is returned to the normal control mode.
B4M0116A
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15. Hydraulic Unit for ABS System

G4M0455
D: INSTALLATION
1) Install relay box cover on hydraulic unit.
2) Install hydraulic unit to bracket.
Tightening torque:
18±5 N⋅m (1.8±0.5 kg-m, 13.0±3.6 ft-lb)
3) Tighten bracket and motor ground lead as a unit.
Tightening torque:
32±10 N⋅m (3.3±1.0 kg-m, 24±7 ft-lb)
4) Connect brake pipes to their correct hydraulic unit con-
nections.
Tightening torque:
15
+3
2N⋅m (1.5+0.3
0.2kg-m, 10.8+2.2
1.4ft-lb)
16. ABS Control Module
A: REMOVAL
1) Remove floor mat located under lower right side of front
seat.
G4M0468
2) Remove screw which secure ABS control module from
the body.
G4M0469
3) Disconnect connector from ABS control module.
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15. Hydraulic Unit for ABS System - 16. ABS Control Module

G4M0455
D: INSTALLATION
1) Install relay box cover on hydraulic unit.
2) Install hydraulic unit to bracket.
Tightening torque:
18±5 N⋅m (1.8±0.5 kg-m, 13.0±3.6 ft-lb)
3) Tighten bracket and motor ground lead as a unit.
Tightening torque:
32±10 N⋅m (3.3±1.0 kg-m, 24±7 ft-lb)
4) Connect brake pipes to their correct hydraulic unit con-
nections.
Tightening torque:
15
+3
2N⋅m (1.5+0.3
0.2kg-m, 10.8+2.2
1.4ft-lb)
16. ABS Control Module
A: REMOVAL
1) Remove floor mat located under lower right side of front
seat.
G4M0468
2) Remove screw which secure ABS control module from
the body.
G4M0469
3) Disconnect connector from ABS control module.
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4-4SERVICE PROCEDURE
15. Hydraulic Unit for ABS System - 16. ABS Control Module

19. Air Bleeding (With TCS model)
A: RULES FOR EFFECTIVE BLEEDING
1) Pressure is not applied to suction pipe by depressing
brake pedal. When any of the following are performed,
bleed air from suction pipe by air bleeding control opera-
tion.
NOTE:
For TCS vehicle, suction pipe is installed between master
cylinder and hydraulic unit to allow flow of brake fluid
between them during ABS and TCS operation.
(1) When brake pipe is disconnected from master cyl-
inder.
(2) When brake pipe between hydraulic unit and mas-
ter cylinder is disconnected.
(3) When fluid is emptied from reservoir tank.
2) The time interval between two brake pedal operations
(from the time when the pedal is released to the time when
it is depressed another time) shall be approximately 3 sec-
onds.
3) The air bleeder on each brake shall be released for 1
to 2 seconds.
B: BLEEDING PROCEDURE WITH AIR
BLEEDING CONTROL
1. BLEEDING PROCEDURE
CAUTION:

The FMVSS No. 116, fresh DOT3 or 4 brake fluid
must be used.

Cover bleeder with waste cloth, when loosening it,
to prevent brake fluid from being splashed over sur-
rounding parts.

Avoid mixing different brands of brake fluid to pre-
vent degrading the quality of the fluid.

Be careful not to allow dirt or dust to get into the
reservoir tank.

During bleeding operation, keep the brake reserve
tank filled with brake fluid to eliminate entry of air.
NOTE:

Brake pedal operating must be very slow.

For convenience and safety, it is advisable to have two
man working.
G4M0434
1) Start air bleeding control operation. <Ref. to [W19C0] or
[W19D0].>
2) Make sure that there is no leak from joints and connec-
tions of the brake system.
3) Bleed air through front RH caliper by operating brake
pedal.
(1) Fit one end of vinyl tube into the air bleeder and put
the other end into a brake fluid container.
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4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

11) Operate FRO (Front Right Outlet) valve and RLO
(Rear Left Outlet) valve to bleed air from hydraulic unit
outlet circuit.
(1) Press TCS OFF switch while depressing brake
pedal.
(2) Make sure ABS warning light illuminates.
(3) Repeatedly depress and release brake pedal 10
times or more while pressing TCS OFF switch.
NOTE:

Air comes out from reservoir tank.
12) Operate FLO (Front Left Outlet) valve and RRO (Rear
Right Outlet) valve to bleed air from hydraulic unit outlet
circuit.
(1) Press TCS OFF switch while depressing brake
pedal.
(2) Make sure TCS warning light illuminates.
(3) Repeatedly depress and release brake pedal 10
times or more while pressing TCS OFF switch.
NOTE:

Air comes out from reservoir tank.

The operations in steps 11) and 12) above can be
switched with each other by operating brake pedal (stop
light switch) while pressing TCS OFF switch.

Repeat procedures 11) and 12) until air no longer comes
out of reservoir tank.
13) Perform these steps for the brakes connecting to the
secondary chamber of master cylinder, first, and then for
the ones connecting to primary chamber. With all proce-
dures completed, fully depress the brake pedal and keep
it in that position for approximately 20 seconds to make
sure that there is no leak evident in the entire system.
14) Turn ignition switch OFF.
15) Perform TCS sequence control. <Ref. to [W20F0].>
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4-4SERVICE PROCEDURE
19. Air Bleeding (With TCS model)

3. CONDITIONS FOR COMPLETION OF AIR
BLEEDING CONTROL
When any of the following conditions occurs, ABS and TCS
warning lights illuminate. Air bleeding control stops, while
the ABS and TCS function will then stop. The brake sys-
tem functions as a conventional brake system.
1) When the speed of at least one wheel reaches 10 km/h
(6 MPH).
2) When terminal No. 4 is separated from diagnosis termi-
nal. (When select monitor is not used.)
3) When pump motor remains ON for two minutes.
4) When TCS valve remains open for two minutes.
5) When outlet valve remains closed for two minutes.
6) When malfunction is detected.
NOTE:
When a malfunction is detected the air bleeding operation
stops and the trouble codes are stored in memory.
B4M0082C
C: AIR BLEEDING CONTROL WITH
DIAGNOSIS CONNECTOR
1) Connect diagnosis terminals to terminal No. 4 of the
diagnosis connector beside driver’s seat heater unit.
B4M0621A
2) Start the engine while pushing TCS OFF switch.
NOTE:
Keep the TCS OFF switch depressed even after the engine
has started.
3) After ABS and TCS warning lights go out, depress
brake pedal within 0.5 seconds.
4) After ensuring TCS ON indicator illuminates, release
TCS OFF switch and brake pedal.
5) Air bleeding control operation starts.
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19. Air Bleeding (With TCS model)

20. Hydraulic Unit for ABS/TCS System
B4M0707A
1ABS/TCS hydraulic
control unit

2Rear-RH outlet

3Front-LH outlet

4Front-RH outlet

5Rear-LH outlet

6Secondary inlet

7Primary inlet
8Secondary suction line

9Primary suction line

10Bumper

11Bracket

12Pressure switch

13Valve relay

14Motor relay
Tightening torque: N⋅m (kg-m, ft-lb)
T1: 7.4±2.0 (0.75±0.2, 5.4±1.4)
T2: 29±7 (3.0±0.7, 21.7±5.1)
T3: 32±10 (3.3±1.0, 24±7)
T4: 38±10 (3.8±1.0, 27±7)
T5: 3.1±1 (0.32±0.1, 2.3±0.7)
A: REMOVAL
1) Disconnect ground cable from battery.
2) Remove canister, air intake and air cleaner case duct
from engine compartment to facilitate removal of hydraulic
unit.
3) Disconnect brake pipes from hydraulic unit.
CAUTION:
Wrap brake pipes with vinyl bag to avoid spilling brake
fluid on vehicle body.
4) Disconnect connector from hydraulic unit.
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20. Hydraulic Unit for ABS/TCS System

C: CHECKING THE HYDRAULIC UNIT ABS
OPERATION
1. CHECKING THE HYDRAULIC UNIT ABS
OPERATION BY PRESSURE GAUGE
1) Lift-up vehicle and remove wheels.
2) Disconnect the air bleeder screws from the FL and FR
caliper bodies.
B4M0633A
3) Connect two pressure gauges to the FL and FR caliper
bodies.
CAUTION:

Pressure gauges used exclusively for brake fluid
must be used.

Do not employ pressure gauge previously used for
transmission since the piston seal is expanded which
may lead to malfunction of the brake.
NOTE:
Wrap sealing tape around the pressure gauge.
4) Bleed air from the pressure gauges.
5) Perform ABS sequence control. <Ref. to [W20D0].>
6) When the hydraulic 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 fluctuation of 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/cm
2, 498 psi)490 kPa (5 kg/cm2, 71 psi)
or less981 kPa (10 kg/cm2, 142 psi)
or more
Rear wheel 3,432 kPa (35 kg/cm
2, 498 psi)490 kPa (5 kg/cm2, 71 psi) or
less981 kPa (10 kg/cm2, 142 psi)
or more
8) Remove pressure gauges and air bleeder screws from
the RL and RR caliper bodies.
9) Connect the air bleeder screws hose to the FL and FR
caliper bodies.
10) Connect two pressure gauges to the RL and RR cali-
per bodies.
11) Bleed air from the pressure gauges and the FL and FR
caliper bodies.
12) Perform ABS sequence control. <Ref. to [W20D0].>
13) When the hydraulic unit begins to work, at first the RR
side performs decompression, holding, and compression,
and then the RL side performs decompression, holding,
and compression.
14) Read values indicated on the pressure gauges and
check if they meet the standard value.
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20. Hydraulic Unit for ABS/TCS System

15) After checking, remove the pressure gauges from cali-
per bodies.
16) Connect the air bleeder screws to RL and RR caliper
bodies.
17) Bleed air from brake line.
2. CHECKING THE HYDRAULIC UNIT ABS
OPERATION WITH BRAKE TESTER
1) Prepare for operating ABS sequence control. <Ref. to
[W20D1] or [W20D2].>
G4M0464
2) Set the front wheels or rear wheels on the brake tester
and set the select lever’s position at“neutral”.
3) Operate the brake tester.
4) Perform ABS sequence control. <Ref. to [W20D1] step
1 or [W20D2] step 1.>
5) Hydraulic unit begins to work; and check the following
working sequence.
(1) The front left wheel performs decompression,
holding, and compression in sequence, and subse-
quently the front right wheel repeats the cycle.
(2) The rear right wheel performs decompression,
holding, and compression in sequence, and subse-
quently the rear left wheel repeats the cycle.
6) Read values indicated on the brake tester and check if
the fluctuation of values, when decompressed and
compressed, meet the standard values.
Unit: N (kg, lb)
Initial value When decompressed When compressed
Front wheel981—1,471
(100—150, 221—331)245 (25, 55) or less 588 (60, 132) or more
Rear wheel981—1,471
(100—150, 221—331)245 (25, 55) or less 588 (60, 132) or more
7) After checking, also check if any irregular brake pedal
tightness is felt.
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20. Hydraulic Unit for ABS/TCS System

D: ABS SEQUENCE CONTROL
1) Under the ABS sequence control, after the hydraulic
unit solenoid valve is driven, the operation of the hydraulic
unit can be checked by means of the brake tester or pres-
sure gauge.
2) ABS sequence control can be started by diagnosis con-
nector or select monitor.
B4M0082C
1. OPERATIONAL GUIDELINES OF THE ABS
SEQUENCE CONTROL WITH DIAGNOSIS
CONNECTOR
1) Connect diagnosis terminals to terminal No. 4 of the
diagnosis connector beside driver’s seat heater unit.
2) Ignition switch is turned to ON.
3) Make sure only the start code (code 11) is shown in
normal condition. <Ref. to 4-4b [T6D1].>
NOTE:
When trouble codes are stored in memory, repair the faulty
parts.
4) Set the speed of all wheels at 10 km/h (6 MPH) or less.
5) Turn ignition switch OFF.
6) Within 0.5 seconds after the ABS and TCS warning
lights go out, depress the brake pedal and hold it immedi-
ately after engine starts.
NOTE:

When the ignition switch is set to on, the brake pedal
must not be depressed.

Engine must operate.

If brake pedal is not depressed within 0.5 seconds after
ABS and TCS warning lights go out, the trouble code mode
comes on.
7) After completion of ABS sequence control, turn ignition
switch OFF.
2. OPERATIONAL GUIDELINES OF THE ABS
SEQUENCE CONTROL WITH SELECT MONITOR
1) Connect select monitor to data link connector beside
driver’s seat heater unit. <Ref. to [W19D0] step 1).>
2) Engine starts.
3) Put select monitor to TCS mode.
4) put select monitor to FBI mode. Make sure code 11 is
indicated.
NOTE:
When trouble codes are stored in memory, repair the faulty
parts.
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20. Hydraulic Unit for ABS/TCS System