LEXUS GS400 2000 Service Repair Manual

F06049
F02821
Hydraulic Brake
BoosterSub±Wire harness S (SST)
FRONT
REAR
AIR BLEEDActuator Checker (SST)
± BRAKEHYDRAULIC BRAKE BOOSTER
BR±43
2151 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
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 ºFRONTº 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 ºSHEET Gº (SST) of ºFRONTº 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
± BRAKEHYDRAULIC BRAKE BOOSTER
2152 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(i) Inspect the front TRAC & VSC solenoid operation.
(1) Push in and hold the ºSA1º and ºSA2º switches si-
multaneously, depress strongly and hold the brake
pedal with stable force.
NOTICE:
Do not keep the ºSA1º and ºSA2º 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 ºSA1º switch and check that the brake
pedal can be depressed.
If the pedal cannot be depressed, replace the hydraulic brake
booster.
(4) Release the ºSA2º 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 ºRHº position.
(2) Push and hold in the MAIN push switch and ºSA2º
switch simultaneously, depress and hold the brake
pedal with stable force.
NOTICE:
Do not keep the MAIN push switch and ºSA2º 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 ºSA2º 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
± BRAKEHYDRAULIC BRAKE BOOSTER
BR±45
2153 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(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 ºLHº position.
(2) Push and hold in the MAIN push switch and ºSA1º
switch simultaneously, depress and hold the brake
pedal with stable force.
NOTICE:
Do not keep the MAIN push switch and ºSA1º 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 ºSA1º 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
ºFRONTº to ºREARº.
(m) Place ºSHEET Gº of ºREARº on the actuator checker.
(n) Jack up and support the vehicle.
(o) Start the engine and run it at idle.

F02830
F02831
BR±46
± BRAKEHYDRAULIC BRAKE BOOSTER
2154 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(p) Inspect the rear TRAC & VSC solenoid.
(1) Release the parking brake pedal and shift the shift
lever to ºLº position.
(2) Push and hold the ºSA3º switch and ºSTRº switch
simultaneously.
NOTICE:

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

Do not keep the ºSA3º 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 ºSA3º switch and ºSTRº 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 ºRHº 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 ºLº 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.

F02832
± BRAKEHYDRAULIC BRAKE BOOSTER
BR±47
2155 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(r) Inspect the left rear ABS solenoid.
(1) Turn the selector switch to ºLHº 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 ºLº 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 left rear wheel rotates.
If the left rear wheel stops, replace the hydraulic brake booster.
(s) Stop the engine and lower the vehicle.
(t) Remove the ºSHEET Gº (SST) and disconnect the actua-
tor checker (SST) and sub±wire harness S (SST) from the
hydraulic brake booster.
(u) Connect the 2 connectors to the actuator.
(v) Clear the DTC (See page DI±389).

BR0JC±04
D01827
LEXUS
Hand±held
Tester
DLC3
BR±4
± BRAKEBRAKE FLUID
2112 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
BRAKE FLUID
BLEEDING
HINT:

If any work is done on the brake system or if air in the
brake lines is suspected, bleed the air from the system.

When bleeding, keep the amount of the fluid within the
line of reservoir between Min. and Max.
NOTICE:

Do not let brake fluid remain on painted surfaces.
Wash it off immediately.

With the reservoir cap removed, when depressing the
brake pedal, the fluid will spray.
1. FILL RESERVOIR WITH BRAKE FLUID
Fluid: SAE J1703 or FMVSS NO. 116 DOT3
2. IN CASE OF USING LEXUS HAND±HELD TESTER:
BLEED HYDRAULIC BRAKE BOOSTER
HINT:
If the hydraulic brake booster has been disassembled, discon-
nect the brake line from the hydraulic brake booster or if the res-
ervoir becomes empty, bleed the hydraulic brake booster.
(a) Turn the ignition switch OFF, depress the brake pedal
more than 40 times.
HINT:
When a pressure in power supply system is released, reaction
force becomes heavy and stroke becomes shorter.
(b) Turn the ignition switch ON, check that the pump stops af-
ter approx. 30 to 40 seconds.
NOTICE:
When the pump does not stop, repeat step (a) and (b) again.
(c) With the ignition switch remained ON, depress the brake
pedal more than 20 times.
(d) Observe the procedure in step 4 and bleed the right and
left front brake caliper.
(e) Holding the brake pedal depressed, bleed the right and
left rear brake caliper.
HINT:
It is not necessary to depress the pedal continuously, as brake
fluid flows out by first depressing.
(f) Connect LEXUS hand±held tester.
(1) Turn the ignition switch OFF, connect the LEXUS
hand±held tester to DLC3.
(2) Turn the ignition switch ON, and select ºAIR
BLEEDINGº on the LEXUS hand±held tester.
HINT:
Please refer to the LEXUS hand±held tester operator's manual
for further details.

F06049
± BRAKEBRAKE FLUID
BR±5
2113 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(g) Bleed right front brake line.
(1) Select ºFR LINEº on the LEXUS hand±held tester.
(2) With ºFR LINEº turned ON with the LEXUS hand±
held tester, depress the brake pedal and hold it to
bleed the right front brake caliper.
(3) Repeat step (2) until there are no more air bubbles
in the fluid.
(h) Bleed left front brake line.
(1) Select ºFL LINEº on the LEXUS hand±held tester.
(2) With ºFL LINEº turned ON with the LEXUS hand±
held tester, depress the brake pedal and hold it to
bleed the left front brake caliper.
(3) Repeat step (2) until there are no more air bubbles
in the fluid.
(i) Bleed rear brake line.
(1) Select ºRR LINEº on the LEXUS hand±held tester.
(2) With ºRR LINEº turned ON with the LEXUS hand±
held tester, bleed the left and right rear brake cali-
per.
(j) Disconnect the LEXUS hand±held tester from DLC3.
(k) Clear the DTC (See page DI±389).
3. IN CASE OF USING ABS ACTUATOR CHECKER
(SST):
BLEED HYDRAULIC BRAKE BOOSTER
HINT:
If the hydraulic brake booster has been disassembled, discon-
nect the brake line from the hydraulic brake booster or if the res-
ervoir becomes empty, bleed the hydraulic brake booster.
(a) Disconnect the 2 connectors from the hydraulic brake
booster.

F02821
Hydraulic Brake
BoosterSub±Wire harness S (SST)
AIR BLEED
FRONT
REARActuator Checker (SST) BR±6
± BRAKEBRAKE FLUID
2114 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(b) 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 ºAIR BLEEDº attached
to the connector of actuator checker.
(c) Connect the red cable of the actuator checker to the bat-
tery positive (+) terminal and the black cable to the nega-
tive (±) terminal.
(d) Turn the ignition switch OFF, depress the brake pedal
more than 40 times.
HINT:
When a pressure in power supply system is released, reaction
force becomes heavy and stroke becomes shorter.
(e) Turn the ignition switch ON, check that the pump stops af-
ter approx. 30 to 40 seconds.
NOTICE:
When the pump does not stop, repeat step (d) and (e) again.
(f) With the ignition switch remained ON, depress the brake
pedal more than 20 times.
(g) Observe the procedure in step 4 and bleed the right and
left front wheel caliper.
(h) Holding the brake pedal depressed, bleed the right and
left rear wheel caliper.
HINT:
It is not necessary to depress the pedal continuously, as brake
fluid flows out by first depressing.

F02823
F02824
F02825
± BRAKEBRAKE FLUID
BR±7
2115 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(i) Bleed right front brake line.
(1) Turn the selector switch of the actuator checker to
the ºFRONT RHº position.
(2) Push and hold in MAIN push switch, depress the
brake pedal and hold it to bleed the right front brake
caliper.
NOTICE:
Do not keep the MAIN switch pushed in for more than 10 se-
conds. When operating it continuously, set the interval of
more than 20 seconds.
(3) Repeat step (2) until there are no more air bubbles
in the fluid.
(j) Bleed left front brake line.
(1) Turn the selector switch of the actuator checker to
the ºFRONT LHº position.
(2) Push and hold in the MAIN push switch, depress the
brake pedal and hold it to bleed the left front brake
caliper.
NOTICE:
Do not keep the MAIN switch pushed in for more than 10 se-
conds. When operating it continuously, set the interval of
more than 20 seconds.
(3) Repeat step (2) until there are no more air bubbles
in the fluid.
(k) Bleed right rear brake line.
(1) Push and hold in the ºSUB LHº and ºSUB RHº
switches, bleed the right rear brake caliper.
NOTICE:
Do not keep the MAIN switch pushed in for more than 10 se-
conds. When operating it continuously, set the interval of
more than 20 seconds.
(2) Repeat step (1) until there are no more air bubbles
in the fluid.

F02851
BR±8
± BRAKEBRAKE FLUID
2116 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(l) Observe the procedure in step (k) and bleed left rear
brake line.
(m) Disconnect the actuator checker (SST) and sub±wire har-
ness (SST) from the actuator.
SST 09990±00150, 09990±00480
(n) Connect the 2 connectors to the hydraulic brake booster.
(o) Clear the DTC (See page DI±389).
4. BLEED BRAKE LINE
(a) Connect the vinyl tube to the brake caliper.
(b) Depress the brake pedal several times, then loosen the
bleeder plug with the pedal held down.
(c) At the point when fluid stops coming out, tighten the
bleeder plug, then release the brake pedal.
(d) Repeat (b) and (c) until all the air in the fluid has been bled
out.
(e) Repeat the above procedure to bleed the brake line for
each wheel.
Torque: 11 N´m (110 kgf´cm, 8 ft´lbf)
5. CHECK FLUID LEVEL IN RESERVOIR
(a) With the ignition switch OFF, depress the brake pedal
more than 40 times.
HINT:
When a pressure in power supply system is released, reaction
force becomes heavy and stroke becomes shorter.
(b) Remove the reservoir cap. Add brake fluid up to the
ºMAXº line.
Fluid: SAE J1703 or FMVSS NO. 116 DOT3