Lexus GS300/400 (2000 year). Manual — part 106

F06049

F02821

Hydraulic Brake
Booster

Sub–Wire harness S (SST)

FRONT

REAR

AIR BLEED

Actuator Checker (SST)

–

BRAKE

HYDRAULIC BRAKE BOOSTER

BR–43

2151

3.

IN CASE OF USING ABS ACTUATOR CHECKER:
INSPECT HYDRAULIC BRAKE BOOSTER OPERA-
TION

(a)

Inspect the battery positive voltage.
Battery positive voltage: 10 – 14 V

(b)

Disconnect the 2 connectors from hydraulic brake boost-
er.

(c)

Connect the actuator checker (SST) to the hydraulic
brake booster side wire harness via the sub–wire harness
S (SST), as shown in the chart below.
SST

09990–00150, 09990–00480

HINT:
Connect the connector with the label of ”FRONT” attached to
the connector of actuator checker.
(d)

Connect the red cable of the checker to the battery posi-
tive (+) terminal and the black cable to the negative (–) ter-
minal.

(e)

Place ”SHEET G” (SST) of ”FRONT” on actuator checker.
SST

09990–00240

(f)

Turn the ignition switch OFF, depress the brake pedal
more than 40 times.

(g)

Check that the brake pedal becomes heavy to depress.

If the pedal does not become to be heavy to depress, check and
replace the brake line and hydraulic brake booster.
(h)

Turn the ignition switch ON, check the pump motor opera-
tion noise.

If the pump motor does not operate, check and replace the wire
harness and pump motor.

F04706

F02828

F02827

BR–44

–

BRAKE

HYDRAULIC BRAKE BOOSTER

2152

(i)

Inspect the front TRAC & VSC solenoid operation.
(1)

Push in and hold the ”SA1” and ”SA2” switches si-
multaneously, depress strongly and hold the brake
pedal with stable force.

NOTICE:
Do not keep the ”SA1” and ”SA2” pushed down for more
than 10 seconds. When operating it continuously, set the
interval of more than 20 seconds.

(2)

Check that the brake pedal cannot be depressed.

If the pedal can be depressed, replace the hydraulic brake
booster.

(3)

Release the ”SA1” switch and check that the brake
pedal can be depressed.

If the pedal cannot be depressed, replace the hydraulic brake
booster.

(4)

Release the ”SA2” switch and check that the brake
pedal can be depressed.

If the pedal cannot be depressed, replace the hydraulic brake
booster.

(j)

Inspect the right front ABS solenoid operation.
(1)

Turn the selector switch to ”RH” position.

(2)

Push and hold in the MAIN push switch and ”SA2”
switch simultaneously, depress and hold the brake
pedal with stable force.

NOTICE:
Do not keep the MAIN push switch and ”SA2” switch
pushed down for more than 10 seconds. When operating
it continuously, set the interval of more than 20 seconds.

(3)

Check that the brake pedal cannot be depressed.

If the pedal can be depressed, replace the hydraulic brake
booster.

(4)

Release the MAIN push switch and ”SA2” switch si-
multaneously and check that the brake pedal can
be depressed.

If the pedal cannot be depressed, replace the hydraulic brake
booster.

(5)

Release the brake pedal.

(6)

Depress and hold the brake pedal with stable force,
push and hold in MAIN push switch.

NOTICE:
Do not keep the MAIN push switch pushed down for more
than 10 seconds. When operating it continuously, set the
interval of more than 20 seconds.

(7)

Check that the brake pedal cannot be depressed.

If the pedal can be depressed, replace the hydraulic brake
booster.

F04707

F02829

–

BRAKE

HYDRAULIC BRAKE BOOSTER

BR–45

2153

(8)

Release the MAIN push switch, and check that the
brake pedal can be depressed.

If the pedal cannot be depressed, replace the hydraulic brake
booster.

(9)

Release the brake pedal.

(k)

Inspect the left front ABS solenoid operation.
(1)

Turn the selector switch to ”LH” position.

(2)

Push and hold in the MAIN push switch and ”SA1”
switch simultaneously, depress and hold the brake
pedal with stable force.

NOTICE:
Do not keep the MAIN push switch and ”SA1” switch
pushed down for more than 10 seconds. When operating
it continuously, set the interval of more than 20 seconds.

(3)

Check that the brake pedal cannot be depressed.

If the pedal can be depressed, replace the hydraulic brake
booster.

(4)

Release the MAIN push switch and ”SA1” switch si-
multaneously, and check that the brake pedal can
be depressed.

If the pedal cannot be depressed, replace the hydraulic brake
booster.

(5)

Release the brake pedal.

(6)

Depress and hold the brake pedal with stable force,
push and hold in MAIN push switch.

NOTICE:
Do not keep the MAIN push switch pushed down for more
than 10 seconds. When operating it continuously, set the
interval of more than 20 seconds.

(7)

Check that the brake pedal cannot be depressed.

If the pedal can be depressed, replace the hydraulic brake
booster.

(8)

Release the MAIN push switch, and check that the
brake pedal can be depressed.

If the pedal cannot be depressed, replace the hydraulic brake
booster.

(9)

Release the brake pedal.

(l)

Turn the ignition switch OFF, then reconnect the connec-
tor of sub–wire harness from the one with label of
”FRONT” to ”REAR”.

(m)

Place ”SHEET G” of ”REAR” on the actuator checker.

(n)

Jack up and support the vehicle.

(o)

Start the engine and run it at idle.

F02830

F02831

BR–46

–

BRAKE

HYDRAULIC BRAKE BOOSTER

2154

(p)

Inspect the rear TRAC & VSC solenoid.
(1)

Release the parking brake pedal and shift the shift
lever to ”L” position.

(2)

Push and hold the ”SA3” switch and ”STR” switch
simultaneously.

NOTICE:

Do not keep the ”STR” switch pushed down for more
than 10 seconds.

Do not keep the ”SA3” switch pushed down for more
than 5 seconds.

When operating it continuously, set the interval of
more than 20 seconds.
(3)

Check that the rear wheels stop.

If the rear wheels rotate, replace the hydraulic brake booster.

(4)

Release the ”SA3” switch and ”STR” switch simulta-
neously.

(5)

Check that the rear wheels rotate.

If the rear wheels stop, replace the hydraulic brake booster.

(q)

Inspect the right rear ABS solenoid.
(1)

Turn the selector switch to ”RH” position.

(2)

Depress the brake pedal several times and release
the brake pedal when the pump begins rotating.
Wait until the pump stops.

(3)

Turn the ignition switch OFF.

(4)

Depress the brake pedal with a force of 343 N (35
kgf, 77 lbf), record the fluid surface in the reservoir
tank of the hydraulic brake booster.

(5)

Press the MAIN push switch for 10 sec., and check
that the fluid surface in the reservoir tank of the hy-
draulic brake booster does not rise up at this time.

If the fluid surface level rises up, replace the hydraulic brake
booster.
NOTICE:
Do not press MAIN push switch for more than 10 sec. When
operating the switch continuously, do it an interval of more
than 20 seconds.

(6)

Start the engine and run it at idle.

(7)

Depress the brake pedal.

(8)

Release the parking brake pedal and shift the shift
lever to ”L” position.

(9)

Once, release the brake pedal. After depressing the
brake pedal with stable force, then push and hold
MAIN push switch.

(10) Check that the right rear wheel rotates.

If the right rear wheel stops, replace the hydraulic brake boost-
er.