Excessive Brake Pedal Travel (No Fluid Leaks and No Air in System) [11/2021 - ]: Procedure

WARNING: This page is about a different car, the 2025 Lexus NX 350h, 2024 Lexus NX 350h, 2023 Lexus NX 350h, and 2022 Lexus NX 350h. However, it is still accessible from the selected car via links, so may be relevant.

BRAKE PROBLEM CHECK

Check the conditions at the time the problem occurred.

Whether a warning light illuminated or the buzzer sounded.
Road surface condition when the problem occurred and just before the problem occurred.
When the problem occurred and how many times the brake pedal was depressed before the problem occurred.
Frequency of the abnormal brake pedal response.

Result

Proceed to
NEXT

Result:

See step 2

CHECK DTC AND FREEZE FRAME DATA

Using the GTS, check DTCs and Freeze Frame Data.

Chassis > Brake Booster > Trouble Codes

Chassis > Brake/EPB > Trouble Codes

HINT:

If there are currently no warnings and the brake pedal travel is not excessive, DTCs may have been cleared after the system returned to normal.
If the brake pedal response returned to normal and there are currently no warnings, the system is normal.

Result

Result	Proceed to
DTCs are not output.	A
DTCs are output.	B

Result:

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

Result:

See step 3

CHECK BRAKE PEDAL

While depressing the brake pedal by hand, check the installation condition of the brake pedal stroke sensor assembly and brake pedal, and check for mechanical malfunctions.

Check and adjust the brake pedal height.

Refer to ADJUSTMENT [11/2021 - ]

Result

Proceed to
NEXT

Result:

See step 4

INSPECT BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY
Refer to PROCEDURE - Step 4

OK

The brake booster with master cylinder assembly is normal.

Result

Proceed to

OK

NG

Result:

OK

USE SIMULATION METHOD TO CHECK. Refer to HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - ]

Result:

NG

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to REMOVAL [11/2021 - ]