Lexus RX (RX 350L, RX450h) 2016-2024 Repair Manual: Brake Hold Operated Indicator Light Circuit

DESCRIPTION

The brake hold operated indicator light illuminates when the brake hold system is operating (vehicle stopped due to brake fluid pressure hold) and turns off when the brake hold system operation is finished (brake fluid pressure decreases).

The brake hold system may not operate depending on vehicle conditions even when the system is in standby mode and the brake hold standby indicator light is illuminated.

If there is a system malfunction that causes brake hold control to be prohibited, when the vehicle is under the following conditions and the brake hold switch (electric parking brake switch assembly) is pressed, the brake hold operated indicator light blinks.

  • Vehicle Conditions:
    1. The driver door is closed.
    2. The driver seat belt is fastened.

HINT:

  • When the engine switch is turned off during brake hold operation, control stops.
  • If brake hold control does not operate even when the vehicle stops, depress on the brake pedal again firmly to stop the vehicle.

    If brake hold control still does not operate, confirm the conditions for brake hold control to operate.

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake actuator assembly), perform "Calibration".

Click here

PROCEDURE

1.

PRE-CHECK

(a) Check that the brake hold standby indicator light operates normally.

Click here

(b) If the brake hold operated indicator light does not illuminate even though the brake hold standby indicator light is illuminated, check that the following brake hold operation (brake fluid pressure is being maintained ) conditions are met.

  1. System is in operation standby state (brake hold standby indicator light is illuminated).
  2. Shift position is not P or R.
  3. Driver is depressing brake pedal and vehicle is fully stopped.
  4. Driver is not depressing accelerator pedal.
  5. Vehicle is not on steep decline.

HINT:

If a malfunction occurs in one of the following systems, the brake hold operated indicator light will blink. If this occurs, perform troubleshooting on the malfunctioning system.

  • Brake system
  • Electric parking brake system
NEXT

2.

CHECK VEHICLE CONTROL HISTORY (VEHICLE STABILITY CONTROL SYSTEM AND ELECTRIC PARKING BRAKE SYSTEM)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Enter the following menus: Chassis / Brake/EPB / Utility / Vehicle Control History (RoB).

(d) Using the Techstream, check for Vehicle Control History.

Click here

Chassis > Brake/EPB > Utility

Tester Display

Vehicle Control History (RoB)

HINT:

If vehicle control history is stored (X2079, X2087, X208A, X208B, X20D7, X20D8, X204C, X2085 or X2088), when the vehicle is under the following vehicle conditions and the brake hold switch (electric parking brake switch assembly) is turned on, the brake hold operated light blinks.

Vehicle Conditions:

  1. The driver door is closed.
  2. The driver seat belt is fastened.

Result

Proceed to

No vehicle control history (X2079, X2087, X208A, X208B, X20D7, X20D8, X204C, X2085 or X2088)

A

Vehicle control history exists (X2079, X2087, X208A, X208B, X20D7, X20D8, X204C, X2085 or X2088)

B

B

PERFORM TROUBLESHOOTING AND REPAIR REGARDING VEHICLE CONTROL HISTORY

A

3.

INSPECT COMBINATION METER ASSEMBLY

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Enter the following menus: Body Electrical / Combination Meter / Active Test.

(d) Perform the Active Test of the combination meter assembly using the Techstream.

Click here

Body Electrical > Combination Meter > Active Test

Tester Display

Indicat. Hold

(e) Check the combination meter assembly.

OK:

The brake hold operated indicator light turns on (flashes) or off in accordance with the Techstream operation.

OK

REPLACE BRAKE ACTUATOR ASSEMBLY

NG

INSPECT METER / GAUGE SYSTEM

    Brake Warning Light Remains ON
    DESCRIPTION This procedure is for troubleshooting when the brake warning light remains on but no DTCs are output. The skid control ECU (brake actuator assembly) controls the brake warning light in the ...

    Brake Hold Standby Indicator Light Circuit
    DESCRIPTION The brake hold standby indicator light turns on if brake hold control is possible when the following conditions required for operation standby are met and the brake hold switch (electric p ...

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    Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual

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