L-SB-0035-21

October 4, 2021

Page 9 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)

K. Remove the brake master cylinder
reservoir filler cap.

Figure 3.

1
c

1

L. Drain the brake fluid in the brake master
cylinder reservoir assembly to near the
MIN line.

Brake Master Cylinder Reservoir Filler Cap

Figure 4.
1

A

2

A

1

Type A

2

Type B

A

MIN Line

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Page 10 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)

M. Connect to Techstream and perform the Zero Down by entering the following menus:
Chassis – ABS-VSC-TRC – Utility – ECB (Electronically Controlled Brake System)
Utility – Zero Down
NOTE
Using the Techstream to perform Zero Down causes the pressurized brake fluid in the
accumulator to be returned to the brake master cylinder reservoir assembly.

N. Confirm the buzzer sound, then turn the ignition OFF.
O. Add brake fluid to the brake master cylinder reservoir assembly until the brake fluid level
is between the MAX and MIN lines on the brake master cylinder reservoir assembly.
P. Turn the power switch ON (IG – ON).
Q. Enter the following menus in Techstream:
Chassis – ABS-VSC-TRAC – Utility – Air Bleeding
R. Select “Actuator has been removed” and bleed the brake system by following the
instructions on Techstream.
CAUTION
Add brake fluid so that the fluid level in the brake master cylinder reservoir assembly
does NOT go below the MIN level.

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Page 11 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)

S. Perform air bleeding per the Techstream instructions below.
Figure 5. Air Bleeding Procedure

Air Bleeding
This function performs
air bleeding to the brake
system.
Caution:
During the air bleeding
operation,
keep the brake fluid in the
Reservoir above the MIN line.

Air Bleeding
Confirm the following
conditions:
 The vehicle is parked.
 Parking brake ON.
 IG ON

Air Bleeding
Select the air bleeding
classification:
1

Click “Next”
 Normal Air Bleeding
● Air Bleeding after Actuator
Removal
 Air Bleeding after removal
of Master Cylinder or
Stroke Simulator

1

Air Bleeding After Actuator Removal Will Discharge Most of the Air

(1) Drain the fluid until the fluid level in the reservoir tank reaches MIN level. (Press on the
brake pedal while the bleeder plug is open.)
(2) Fasten the bleeder plug and add the fluid until the fluid level in the reservoir tank
reaches MAX level. Repeat substeps A and B twice.
(3) Discharge the brake fluid by pumping the brake pedal (depress the pedal a few times)
and loosen the bleeder plug with the brake pedal depressed and release the pedal
after the plug is fastened. Repeat substep C 20 times.

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Page 12 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)
Figure 6. Air Bleeding Procedure (continued)

Air Bleeding

Air Bleeding

Air Bleeding

[work name]

[work name]

[work name]

Conduct the following:
1. Turn IG OFF.
2. Disconnect 2 Brake
Booster Pump
Connectors.
Reference:
If the connectors are already
disconnected, this procedure
is not necessary.
3. Turn IG ON.

Conduct the following:
1. Connect a vinyl tube to
the bleeder plug in the front
right wheel.
2. After depressing the brake
pedal a few times, loosen
the bleeder plug while the
brake pedal is depressed.

3. Once the brake fluid stops
flowing,

1

Click “Next”
Procedure 3 will be displayed

Click “Next”

1

These Steps Must Be Repeated 20 Times

Figure 7. Air Bleeding Procedure (continued)

Air Bleeding

Air Bleeding

[work name]

[work name]

Conduct the following:
1. Connect a vinyl tube to the
bleeder plug in the front
left wheel.
2. After depressing the brake
pedal a few times, loosen the
bleeder plug with the brake
pedal depressed.

3. Once the brake fluid stops,
fasten the bleeder plug and
release the brake pedal.
Conduct procedures 1 through
3 repeatedly until air is
completely discharged.
1

Click "Next"

Click “Next”
Procedure 3 will be displayed

1

These Steps Must Be Repeated 20 Times

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Page 13 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)

T. AFTER the solenoid is moved for 40 seconds discharging brake fluid, fasten the bleeder
plug and release the brake pedal.
Figure 8. Air Bleeding Procedure (continued)

Air Bleeding

Air Bleeding

Air Bleeding

[work name]

[work name]

[work name]

Conduct the following:
1. Turn IG OFF.
Caution:
After the IG OFF, do not
open/close doors or do not
conduct the brake operation.
2. Connect 2 brake booster
pump connectors.
3. Turn IG ON.

Loosen the bleeder plug on
the rear right wheel. In the
next screen, the solenoid will
be moved for 40 seconds.
Caution:
Brake fluid may gush out.

Processing

Click “Next”

Click “Next”

Figure 9. Air Bleeding Procedure (continued)

Air Bleeding

Air Bleeding

Air Bleeding

[work name]

[work name]

[work name]

Fasten the bleeder plug on
the rear right and click “Next.”

Conduct the following:
1. Conduct a vinyl tube to the
bleeder plug on the rear
left wheel.
2. Depress the brake pedal.
3. Loosen the bleeder plug on
the rear left wheel while the
break pedal is depressed.

Conduct the following:
1. Connect a vinyl tube to the
bleeder plug on the rear
right wheel.
2. Depress the brake pedal.
3. Loosen the bleeder plug on
the rear right wheel while
the brake pedal is
depressed.
1

1

These Steps Must Be Repeated 20 Times

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Page 14 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)
Figure 10. Air Bleeding Procedure (continued)

Air Bleeding

Air Bleeding

Air Bleeding

[work name]

[work name]

[work name]

1/5

1/5
Processing

In the next screen, the
accumulator will
be depressurized.
It takes 20 seconds
to depressurize.
Click “Next.”

1/5
IG OFF→IG ON
Once the ABS pump stops,
click “Next.”

Please wait for 20 seconds.
Remaining Time
Sec.

NOTE
The steps above MUST be repeated five times.

Figure 11. Air Bleeding Procedure (continued)

Air Bleeding
[work name]
Air Bleeding is completed.
To conduct another
Air Bleeding, click “Next.” To
end, click “End.”

Air Bleeding

11. Tighten the bleeder plugs once the air bleeding is completed.
Torque: 8.3 N*m (85 kgf*cm, 73 in*lbf)

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Page 15 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)

12. Perform the Techstream Active Test to forcefully move the valve in the actuator to complete
air bleeding by entering the following menus in Techstream:
Chassis – ABS-VSC-TRC – Active Test – Actuator Air Bleeding Pattern
NOTE
Perform the above operation five times.

Figure 12. Techstream Screen Image (Chassis – ABS-VSC-TRC)

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Brake Squawk/Knock Noise
Repair Procedure (continued)
Figure 13. Techstream Screen Image (Active Test)

© 2021 Lexus, a division of Toyota Motor Sales, USA

Page 16 of 19

L-SB-0035-21

October 4, 2021

Brake Squawk/Knock Noise
Repair Procedure (continued)
Figure 14. Techstream Screen Image (Actuator Air Bleeding Pattern)

Figure 15. Techstream Screen Image

© 2021 Lexus, a division of Toyota Motor Sales, USA

Page 17 of 19

L-SB-0035-21

October 4, 2021

Page 18 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)

13. Perform the linear valve offset learning and the brake pedal stroke sensor zero-point learning.
NOTE
BEFORE air bleeding, the linear valve offset learning and brake pedal stroke sensor zero-point
value memories were deleted. ONLY the linear valve offset learning and brake pedal stroke sensor
zero-point learning should be performed.

Refer to TIS, applicable model and model year Repair Manual:


2016 – 2018 RX 450h:
Brake – Brake Control/Dynamic Control System – “Brake Control / Dynamic Control
Systems: Electronically Controlled Brake System: Initialization”



2019 RX 450h:
Brake – Brake Control/Dynamic Control System – “Brake Control / Dynamic Control
Systems: Electronically Controlled Brake System: Initialization”



2020 – 2021 RX 450h:
Brake – Brake Control/Dynamic Control System – “Brake Control / Dynamic Control
Systems: Electronically Controlled Brake System: Initialization”

14. Delete ANY DTCs.
Refer to TIS, applicable model and model year Repair Manual:


2016 – 2018 RX 450h:
Brake – Brake Control/Dynamic Control System – “Brake Control / Dynamic Control
Systems: Electronically Controlled Brake System: DTC Check / Clear”



2019 RX 450h:
Brake – Brake Control/Dynamic Control System – “Brake Control / Dynamic Control
Systems: Electronically Controlled Brake System: DTC Check / Clear”



2020 – 2021 RX 450h:
Brake – Brake Control/Dynamic Control System – “Brake Control / Dynamic Control
Systems: Electronically Controlled Brake System: DTC Check / Clear”

© 2021 Lexus, a division of Toyota Motor Sales, USA

L-SB-0035-21

October 4, 2021

Page 19 of 19

Brake Squawk/Knock Noise
Repair Procedure (continued)

15. Turn the ignition OFF.

16. Disconnect the Techstream from the DLC3.

17. Inspect for brake fluid leakage.

18. Inspect and adjust the amount of the brake fluid.
Refer to TIS, applicable model and model year Repair Manual:


2016 – 2021 RX 450h:
Brake – Brake Control/Dynamic Control System – “Brake System (Other): Brake Fluid:
On-Vehicle Inspection

19. Install the brake master cylinder reservoir filler cap assembly.

20. Test-drive the vehicle to confirm the squawk/knock noise is no longer present.

© 2021 Lexus, a division of Toyota Motor Sales, USA