Lexus RX (RX 350L, RX450h) 2016-2022 Repair Manual: Brake Warning Light (Yellow) Remains On

DESCRIPTION

This procedure is for troubleshooting when the brake warning light (yellow) remains on but no DTCs are output.

The skid control ECU (brake actuator assembly) controls the brake warning light (yellow) in the combination meter assembly via CAN communication.

CAUTION / NOTICE / HINT

NOTICE:

  • The electric parking brake may still operate up to 20 seconds after the engine switch is turned off. Before disconnecting connectors or fuses, turn the engine switch off and wait 20 seconds or more.
  • After replacing the skid control ECU (brake actuator assembly), perform "Calibration".

    Click here

  • When replacing the skid control ECU (brake actuator assembly), operate the electric parking brake switch (electric parking brake switch assembly) as the parking brake indicator light (red) blinks when the engine switch is first turned on (IG).

PROCEDURE

1.

CHECK VEHICLE CONTROL HISTORY (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) 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 when the electric parking brake system is suspended, the brake warning light (yellow) illuminates.

Result

Proceed to

There is no vehicle control history for when the electric parking brake system was suspended.

A

There is vehicle control history for when the electric parking brake system was suspended.

B

B

ERFORM TROUBLESHOOTING AND REPAIR REGARDING VEHICLE CONTROL HISTORY

A

2.

INSPECT COMBINATION METER ASSEMBLY (BRAKE WARNING LIGHT (YELLOW))

(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

ECB Warning

(e) Check the combination meter assembly.

OK:

The brake warning light (yellow) turns on or off in accordance with Techstream operation.

OK

REPLACE SKID CONTROL ECU (BRAKE ACTUATOR ASSEMBLY)

NG

INSPECT METER / GAUGE SYSTEM

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    Electric Parking Brake System AUTO Function Circuit
    DESCRIPTION The skid control ECU (brake actuator assembly) receives shift position signals from the ECM via CAN communication to control the electric parking brake system AUTO function (IG-OFF linked ...

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

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

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