Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual: TRAC does not Operate

Lexus RX (RX 350L, RX450h) 2016-2026 Repair Manual / Brake / Brake Control / Dynamic Control Systems / Vehicle Stability Control System / TRAC does not Operate

DESCRIPTION

When TRAC or VSC is operating, the skid control ECU (brake actuator assembly) blinks the slip indicator light to inform the driver that slippage occurred.

When in VSC off mode, or TRAC and VSC are disabled, the multi-information display in the combination meter assembly displays TRAC OFF message and the VSC OFF indicator light illuminates to inform the driver.

When a communication malfunction with the ECM is detected, TRAC and VSC are disabled. Also when the system is malfunctioning, TRAC and VSC are disabled and the indicator lights of related systems illuminate.

CAUTION / NOTICE / HINT

NOTICE:

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

Click here

PROCEDURE

1.

BRAKE PROBLEM CHECK

(a) Check if the slip indicator light was illuminated when TRAC did not operate.

OK:

The slip indicator light was illuminated.

HINT:

When a DTC is stored, the slip indicator light is illuminated and TRAC does not operate due to the fail-safe function.

(b) Check the operation condition of the VSC OFF switch (combination switch assembly) when TRAC did not operate.

OK:

The VSC OFF switch (combination switch assembly) had been operated to turn off TRAC when TRAC did not operate.

HINT:

When the multi-information display in the combination meter assembly displays TRAC OFF message, TRAC does not operate.

OK

END
NG

2.

CHECK VEHICLE

(a) Connect the Techstream to the DLC3.

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

(c) Read the DTCs following the prompts on the Techstream. Enter the following menus: Chassis / Brake/EPB / Trouble Codes.

Chassis > Brake/EPB > Trouble Codes

(d) Check the DTCs that are output.

OK:

DTCs are not output.

(e) Operate the VSC OFF switch (combination switch assembly) and check that the multi-information display in the combination meter assembly displays TRAC OFF message and the VSC OFF indicator light illuminates in accordance with the operation of the switch.

OK:

The multi-information display in the combination meter assembly displays TRAC OFF message and the VSC OFF indicator light illuminates in accordance with the operation of the switch.

NG

INSPECT COMBINATION SWITCH ASSEMBLY

OK

3.

PERFORM DEALER MODE (SIGNAL CHECK) INSPECTION (SPEED SENSOR CHECK)

(a) Enter the following menus: Chassis / Brake/EPB / Utility / Signal Check.

(b) Using the Techstream, perform a Dealer Mode (Signal Check) inspection sensor check and check that speed sensor Dealer Mode (Signal Check) inspection items change from incomplete to complete.

Click here

Chassis > Brake/EPB > Utility

Tester Display

Signal Check

OK:

Speed sensor Dealer Mode (Signal Check) inspection items change from incomplete to complete.

NG

INSPECT AND REPAIR MALFUNCTIONING SPEED SENSOR CIRCUIT
OK

4.

PERFORM OPERATION CHECK DRIVING

(a) Operate the VSC OFF switch (combination switch assembly) and check that the system is not in TRAC off mode or VSC off mode.

(b) Check that no DTCs are output and that each warning light is not illuminated.

(c) Start off the vehicle on a low friction surface and check that TRAC operates when attempting to make the drive wheels slip.

OK:

TRAC operates when slip occurs when starting off.

NOTICE:

  • Even when the system is normal, VSC may not operate when the vehicle speed is low or TRAC may not operate due to a malfunction. Make sure that only the drive wheels slip during the procedure.
  • When confirming that the slip indicator light blinks, do not slip the drive wheels longer than necessary. Whether TRAC operated or not can be checked by reading the Vehicle Control History (RoB) when the system operated.

    Click here

  • Pay attention to your surroundings when performing the procedure and depress the accelerator pedal with caution.
OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE BRAKE ACTUATOR ASSEMBLY

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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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