Lexus GS300/400 (2000 year). Manual - part 105

D01827

–

BRAKE

HYDRAULIC BRAKE BOOSTER

BR–39

2147

2.

IN CASE OF USING LEXUS HAND–HELD TESTER:
INSPECT HYDRAULIC BRAKE BOOSTER OPERA-
TION

(a)

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

(b)

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

(c)

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.
(d)

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 (See page 

BR–53

).

(e)

Connect the LEXUS hand–held tester.
(1)

Connect the LEXUS hand–held tester to the DLC3.

(2)

Turn the ignition switch ON.

(3)

Select the ”ACTIVE TEST” mode on the LEXUS
hand–held tester.

HINT:

Please refer to the LEXUS hand–held tester operator’s
manual for further details.

To protect the solenoids, hand–held tester turns OFF au-
tomatically 2 secs. after every solenoid has been turned
ON.

(f)

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

Select ”SA1” and ”SA2” on the LEXUS hand–held
tester.

(2)

With ”SA1” and ”SA2” turned ON simultaneously
with the LEXUS hand–held tester, depress the
brake pedal with stable force and check that the
pedal cannot be depressed.

HINT:
To protect the solenoids, LEXUS hand–held tester turns OFF
automatically 2 sec. after every solenoid has been turned ON.
If the pedal can be depressed, replace the hydraulic brake
booster.
NOTICE:
When operating it continuously, set the interval of more
than 20 seconds.

(3)

Once, release the brake pedal.

BR–40

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BRAKE

HYDRAULIC BRAKE BOOSTER

2148

(4)

When the solenoids are OFF, after depressing the
brake pedal again and check that the brake pedal
can be depressed.

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

Inspect the front ABS solenoid operation.
(1)

Select ”SFRH” and ”SFLH” on the LEXUS hand–
held tester.

(2)

With ”SFRH” and ”SFLH” turned ON simultaneously
with the LEXUS hand–held tester, depress the
brake pedal with stable force and check that the
brake pedal cannot be depressed.

HINT:
To protect the solenoids, hand–held tester turns OFF automati-
cally 2 sec. after every solenoid has been turned ON.
If the pedal can be depressed, replace the hydraulic brake
booster.

(3)

Once, release the brake pedal when the solenoids
are OFF, check that the brake pedal can be de-
pressed.

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

(4)

Once, release the brake pedal. After depressing
and holding the brake pedal with stable force, turn
the SFRH and SFRR solenoids ON simultaneously.

HINT:
To protect the solenoids, hand–held tester turns OFF automati-
cally 2 sec. after every solenoid has been turned ON.

(5)

When the solenoids are OFF, check that the brake
pedal can be depressed.

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

(6)

Once, release the brake pedal. After depressing
and holding the brake pedal with stable force, turn
the SFLH and SFLR solenoids ON simultaneously.

HINT:
To protect the solenoids, hand–held tester turns OFF automati-
cally 2 sec. after every solenoid has been turned ON.

(7)

When the solenoids are OFF, check that the brake
pedal can be depressed.

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

Jack up and support the vehicle.

(i)

Release the parking brake pedal.

(j)

Shift the shift lever to ”N” position and check that the rear
wheels by rotating them by hand.

(k)

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

Select the ”SA3” and ”STR” on the LEXUS hand–
held tester.

–

BRAKE

HYDRAULIC BRAKE BOOSTER

BR–41

2149

(2)

Turn the ”SA3” and ”STR” ON simultaneously with
the LEXUS hand–held tester, and check that the
rear wheels by does not rotate by hand.

HINT:
When rotating the wheel fast, the fail–safe function is activated
and judgement cannot be made properly. So rotate the wheel
as slowly as possible.
If the rear wheels rotate, replace the hydraulic brake booster.

(3)

Turn the ”SA3” and ”STR” OFF simultaneously, and
check that the rear wheels by rotating them by
hand.

HINT:

To protect the solenoids, LEXUS hand–held tester turns
OFF automatically 2 sec. after every solenoid has been
turned ON.

When rotating the wheel fast, the fail–safe function is acti-
vated and judgement cannot be made properly. So rotate
the wheel as slowly as possible.

NOTICE:
When operating it continuously, set the interval of more
than 20 secs.
If the rear wheels stop, replace the hydraulic brake booster.
(l)

Inspect the right rear ABS solenoid.
(1)

Select the ”SA3”, ”STR” and ”SRRH”, on the LEXUS
hand–held tester.

(2)

Turn the ”SA3”, ”STR” and ”SRRH” ON simulta-
neously with the LEXUS hand–held tester, and
check that the right rear wheel by rotating it by hand.

HINT:

To protect the solenoids, LEXUS hand–held tester turns
OFF automatically 2 sec. after every solenoid has been
turned ON.

When rotating the wheel fast, the fail–safe function is acti-
vated and judgement cannot be made properly. So rotate
the wheel as slowly as possible.

When solenoid is OFF, the wheel might stop temporarily.
However if the wheel rotates again, the function works
normally.

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

(3)

Turn the ”SA3”, ”STR” and ”SRRH” OFF, and check
that the right rear wheel by rotating it by hand.

HINT:

To protect the solenoids, LEXUS hand–held tester turns
OFF automatically 2 sec. after every solenoid has been
turned ON.

When rotating the wheel fast, the fail–safe function is acti-
vated and judgement cannot be made properly. So rotate
the wheel as slowly as possible.

If the right rear wheel stop, replace the hydraulic brake booster.

BR–42

–

BRAKE

HYDRAULIC BRAKE BOOSTER

2150

(4)

Depress the pedal with stable force, then turn the
”SRRH” and ”SRRR” ON simultaneously.

(5)

When the solenoids are ON, check that the right
rear wheel by rotating it by hand.

(m)

Inspect the left rear ABS solenoid operation.
(1)

Select the ”SA3”, ”STR” and ”SRLH” on the LEXUS
hand–held tester.

(2)

Turn the ”SA3”, ”STR” and ”SRLH” ON with LEXUS
hand–held tester, and check that the left rear wheel
by rotating it by hand.

HINT:
When rotating the wheel fast, the fail–safe function is activated
and judgement cannot be made properly. So rotate the wheel
as slowly as possible.
If the rear wheels stop, replace the hydraulic brake booster.

(3)

Turn the ”SA3”, ”STR” and ”SRLH” OFF and check
that the left rear wheel by rotating it by hand.

HINT:

To protect the solenoids, LEXUS hand–held tester turns
OFF automatically 2 sec. after every solenoid has been
turned ON.

When rotating the wheel fast, the fail–safe function is acti-
vated and judgement cannot be made properly. So rotate
the wheel as slowly as possible.

When solenoid is OFF, the wheel might stop temporarily.
However if the wheel rotates again, the function works
normally.

If the left rear wheel stop, replace the hydraulic brake booster.

(4)

Depress the pedal with stable force, then turn the
”SRLH” and ”SRLR” ON simultaneously.

HINT:
To protect the solenoids, LEXUS hand–held tester turns OFF
automatically 2 sec. after every solenoid has been turned ON.

(5)

When the solenoids are ON, check that the left rear
wheel by rotating it by hand.

HINT:
When rotating the wheel fast, the fail–safe function is activated
and judgement cannot be made properly. So rotate the wheel
as slowly as possible.
(n)

Lower the vehicle.

(o)

Disconnect the LEXUS hand–held tester.