SUBARU LEGACY 1997 Service Repair Manual

3. CONDITIONS FOR COMPLETION OF TCS
SEQUENCE CONTROL
When the following conditions develop, the TCS sequence
control stops and ABS and TCS warning lights come on
while the ABS and TCS function will then stop. The brake
system 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 ground. (When
select monitor is not used.)
3) When the brake pedal is depressed during sequence
control and the braking lamp switch is set to ON.
4) When TCS OFF switch is released. (When select moni-
tor is not used.)
5) After completion of the TCS sequence control.
6) When output signal to break TCS control is emitted from
ECM.
7) When malfunction is detected.
NOTE:
When malfunction has been detected and the TCS
sequence control operation has stopped, the trouble codes
are stored in memory.
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4-4SERVICE PROCEDURE
20. Hydraulic Unit for ABS/TCS System

4. CONDITIONS FOR TCS SEQUENCE CONTROL
B4M0642A
NOTE:
When select monitor is used, control operation starts at
point A. It is not required to operate TCS OFF switch for
starting control operation. The patterns from IGN key ON
to point A show operation is started by diagnosis connec-
tor.
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4-4SERVICE PROCEDURE
20. Hydraulic Unit for ABS/TCS System

B4M0628
G: INSTALLATION
1) Install hydraulic unit and bracket.
Tightening torque:
32±7 N⋅m (3.3±0.7 kg-m, 23.9±5.1 ft-lb)
2) Connect brake pipes to their correct hydraulic unit con-
nections. <Ref. to 4-4 [W18A3].>
3) Connect connector to hydraulic unit.
4) Install canister.
5) Install air cleaner case.
6) Install air intake duct.
7) Connect ground cable to battery.
CAUTION:
Cover relay securely with rubber boot.
21. ABS/TCS Control Module
A: REMOVAL
1) Disconnect ground cable from battery.
2) Remove floor mat located under lower right side of front
seat.
B4M0643A
3) Remove screw which secure ABS/TCS control module
from the body.
4) Disconnect connector from ABS/TCS control module.
B: INSPECTION
Check that connector is connected correctly and that con-
nector terminal sliding resistance is correct.
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4-4SERVICE PROCEDURE
20. Hydraulic Unit for ABS/TCS System - 21. ABS/TCS Control Module

B4M0628
G: INSTALLATION
1) Install hydraulic unit and bracket.
Tightening torque:
32±7 N⋅m (3.3±0.7 kg-m, 23.9±5.1 ft-lb)
2) Connect brake pipes to their correct hydraulic unit con-
nections. <Ref. to 4-4 [W18A3].>
3) Connect connector to hydraulic unit.
4) Install canister.
5) Install air cleaner case.
6) Install air intake duct.
7) Connect ground cable to battery.
CAUTION:
Cover relay securely with rubber boot.
21. ABS/TCS Control Module
A: REMOVAL
1) Disconnect ground cable from battery.
2) Remove floor mat located under lower right side of front
seat.
B4M0643A
3) Remove screw which secure ABS/TCS control module
from the body.
4) Disconnect connector from ABS/TCS control module.
B: INSPECTION
Check that connector is connected correctly and that con-
nector terminal sliding resistance is correct.
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4-4SERVICE PROCEDURE
20. Hydraulic Unit for ABS/TCS System - 21. ABS/TCS Control Module

C: INSTALLATION
1) Connect connector to ABS/TCS control module.
2) Install ABS/TCS control module on the body.
CAUTION:

When installing seat rail, be careful no to have the
harness caught in the rail.

Cover the connector completely with rubber boot.
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4-4SERVICE PROCEDURE
21. ABS/TCS Control Module

22. ABS Control Module and Hydraulic
Control Unit (ABSCM&H/U) (ABS 5.3i
Type)
B4M1220A
1Stud bolt

2Damper

3ABS control module and hydraulic
control unit

4Front-LH outlet

5Secondary inlet
6Front-RH outlet

7Primary inlet

8Rear-LH outlet

9Rear-RH outlet

10Bracket
Tightening torque: N⋅m (kg-m, ft-lb)
T1: 18±5 (1.8±0.5, 13.0±3.6)
T2: 29±7 (3.0±0.7, 21.7±5.1)
T3: 32±10 (3.3±1.0, 24±7)
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4-4SERVICE PROCEDURE
22. ABS Control Module and Hydraulic Control Unit (ABSCM&H/U) (ABS 5.3i Type)

A: REMOVAL
1) Disconnect ground cable from battery.
2) Remove air intake duct from engine compartment to
facilitate removal of ABSCM&H/U.
3) Use an air-gun to get rid of water around the
ABSCM&H/U.
CAUTION:
The contact will be insufficient if the terminal gets wet.
B4M1224A
4) Pull on the lock of the ABSCM&H/U connector to
remove it.
5) Disconnect connector from ABSCM&H/U.
CAUTION:
Be careful not to let water or other foreign matter con-
tact the ABSCM&H/U terminal.
6) Unlock cable clip.
7) Disconnect brake pipes from ABSCM&H/U.
CAUTION:
Wrap brake pipes with vinyl bag to avoid spilling brake
fluid on vehicle body.
B4M1222
8) Remove ABSCM&H/U from engine compartment.
CAUTION:

ABSCM&H/U cannot be disassembled. Do not
attempt to loosen bolts and nuts.

Do not drop or bump ABSCM&H/U.

Do not turn the ABSCM&H/U upside down or place
it on its side.

Be careful to prevent foreign particles from getting
into ABSCM&H/U.

Apply a coat of rust-preventive wax (Nippeco LT or
GB) to bracket attaching bolt after tightening.

Do not pull harness disconnecting harness connec-
tor.
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4-4SERVICE PROCEDURE
22. ABS Control Module and Hydraulic Control Unit (ABSCM&H/U) (ABS 5.3i Type)

B: INSPECTION
1) Check connected and fixed condition of connector.
B4M1248A
2) Check specifications of the mark with ABSCM&H/U.
Mark Model
C3 AWD AT
C4 AWD MT
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.
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22. 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 4-4 [W22D0].>
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 less3,432 kPa (35 kg/cm2, 498 psi)
or more
Rear wheel 3,432 kPa (35 kg/cm
2, 498 psi)490 kPa (5 kg/cm2, 71 psi)
or less3,432 kPa (35 kg/cm2, 498 psi)
or more
8) Remove pressure gauges from FL and FR caliper bod-
ies.
9) Remove air bleeder screws from the RL and RR caliper
bodies.
10) Connect the air bleeder screws to the FL and FR cali-
per bodies.
11) Connect two pressure gauges to the RL and RR cali-
per bodies.
12) Bleed air from the pressure gauges and the FL and FR
caliper bodies.
13) Perform ABS sequence control.
<Ref. to 4-4 [W22D0].>
14) 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.
15) Read values indicated on the pressure gauges and
check if they meet the standard value.
16) After checking, remove the pressure gauges from cali-
per bodies.
17) Connect the air bleeder screws to RL and RR caliper
bodies.
18) Bleed air from brake line.
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22. ABS Control Module and Hydraulic Control Unit (ABSCM&H/U) (ABS 5.3i Type)

G4M0462
2. CHECKING THE HYDRAULIC UNIT ABS
OPERATION WITH BRAKE TESTER
1) In the case of AWD AT vehicles, install a spare fuse with
the FWD connector in the engine compartment to simulate
FWD vehicles.
2) Prepare for operating ABS sequence control. <Ref. to
4-4 [W22D1] or 4-4 [W22D2].>
G4M0464
3) Set the front wheels or rear 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 4-4 [W22D1]
step 1 or 4-4 [W22D2] 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 fluctuation of values, when decompressed and
compressed, meet the standard values.
Unit: N (kg, lb)
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.
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22. ABS Control Module and Hydraulic Control Unit (ABSCM&H/U) (ABS 5.3i Type)