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Home >> Toyota >> 2024 >> Corolla LE >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 74 (Electronically Controlled Brake System (HEV) - Diagnostic Codes (6 Of 6), Symptom Tests & Circuit Tests) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model) >> TRAC does not Operate [01/2019 - 09/2022] >> Procedure

TRAC does not Operate [01/2019 - 09/2022]: Procedure

WARNING: This page is about a different variant/trim than selected.
  1. BRAKE PROBLEM CHECK 
    1. Check if the slip indicator light was illuminated when TR(A)C did not operate.

      OK

      The slip indicator light was illuminated.

      HINT: 

      When a DTC is stored, the slip indicator light is illuminated and TR(A)C does not operate due to the fail-safe function.

    2. Check the operation condition of the VSC OFF switch (combination switch assembly) when TR(A)C did not operate.

      OK

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

      HINT: 

      When the multi-information display in the combination meter assembly displays "Traction Control Turned Off", TR(A)C does not operate.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END 

    Result: 

    NG 

    See step  2

  2. CHECK DTC 
    1. Clear the DTCs.

      Refer to DTC CHECK / CLEAR [01/2019 - 09/2022]

      Chassis > ABS/VSC/TRAC > Clear DTCs 

    2. Turn the power switch off.
    3. Turn the power switch on (IG).
    4. Check the DTCs (electronically controlled brake system) that are output.

      Refer to DTC CHECK / CLEAR [01/2019 - 09/2022]

      Chassis > ABS/VSC/TRAC > Trouble Codes 

      Result

      Result Proceed to
      DTCs are not output. A
      Electronically controlled brake system DTCs are output. B

    Result: 

    REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to  DIAGNOSTIC TROUBLE CODE CHART [01/2019 - 04/2020]  , or refer to  DIAGNOSTIC TROUBLE CODE CHART [04/2020 - 09/2022] 

    Result: 

    See step  3

  3. CHECK VEHICLE 
    1. Operate the VSC OFF switch (combination switch assembly) and check that the multi-information display in the combination meter assembly displays "Traction Control Turned Off" 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 "Traction Control Turned Off" and the VSC OFF indicator light illuminates in accordance with the operation of the switch.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT VSC OFF SWITCH CIRCUIT. Refer to  VSC OFF Switch Circuit [01/2019 - 09/2022]  

    Result: 

    OK 

    See step  4

  4. PERFORM TEST MODE (SIGNAL CHECK) INSPECTION (SPEED SENSOR CIRCUIT) 
    1. Using the Techstream, perform a Test Mode (Signal Check) inspection sensor check and check that speed sensor Test Mode (Signal Check) inspection items change from incomplete to complete.

      Refer to TEST MODE PROCEDURE [01/2019 - 09/2022]

      Chassis > ABS/VSC/TRAC > Utility 

      Tester Display
      Signal Check

      OK

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

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT AND REPAIR MALFUNCTIONING SPEED SENSOR CIRCUIT 

    Result: 

    OK 

    See step  5

  5. PERFORM OPERATION CHECK DRIVING 
    1. Operate the VSC OFF switch (combination switch assembly) and check that the system is not in TR(A)C off mode or VSC off mode.
    2. Check that no DTCs are output and that each warning light is not illuminated.
    3. Start off the vehicle on a low friction surface and check that TR(A)C operates when attempting to make the drive wheels slip.

      OK

      TR(A)C operates when slip occurs when starting off.

      NOTE:
      • Even when the system is normal, VSC may not operate when the vehicle speed is low or TR(A)C 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 TR(A)C operated or not can be checked by reading the Freeze Frame Data when the system operated.
      • Pay attention to your surroundings when performing the procedure and depress the accelerator pedal with caution.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [06/2018 - ] 

    Result: 

    NG 

    REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY. Refer to  REMOVAL [01/2019 - 09/2022]