Last Modified: 05-13-2024 6.11:8.1.0 Doc ID: RM100000001G7AN
Model Year Start: 2020 Model: Corolla Prod Date Range: [01/2019 - 09/2022]
Title: BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): TRAC does not Operate; 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]

TRAC does not Operate

DESCRIPTION

When ABS, TR(A)C or VSC is operating, the skid control ECU (brake booster with master cylinder assembly) blinks the slip indicator light to inform the driver that slippage occurred.

When in VSC off mode, or TR(A)C and VSC are disabled, the multi-information display in the combination meter assembly displays "Traction Control Turned Off" and the VSC OFF indicator light illuminates to inform the driver.

When a communication malfunction with the hybrid vehicle control ECU is detected, TR(A)C and VSC are disabled. Also when the system is malfunctioning, TR(A)C and VSC are disabled and the indicator lights of related systems illuminate.

CAUTION / NOTICE / HINT

NOTICE:

After replacing the skid control ECU (brake booster with master cylinder assembly), perform linear solenoid valve offset learning, ABS holding solenoid valve learning, yaw rate and acceleration sensor zero point calibration and system information memorization after performing "Reset Memory".

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): INITIALIZATION

PROCEDURE

1.

BRAKE PROBLEM CHECK

(a) 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.

(b) 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.

OK

END
NG

2.

CHECK DTC

(a) Clear the DTCs.

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DTC CHECK / CLEAR

Chassis > ABS/VSC/TRAC > Clear DTCs

(b) Turn the power switch off.

(c) Turn the power switch on (IG).

(d) Check the DTCs (electronically controlled brake system) that are output.

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DTC CHECK / CLEAR

Chassis > ABS/VSC/TRAC > Trouble Codes

Result

Proceed to

DTCs are not output.

A

Electronically controlled brake system DTCs are output.

B
B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS 2020 MY Corolla Corolla HV [01/2019 - 04/2020]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART 2021 - 2022 MY Corolla Corolla HV [04/2020 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): DIAGNOSTIC TROUBLE CODE CHART

A

3.

CHECK VEHICLE

(a) 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.

NG

INSPECT VSC OFF SWITCH CIRCUIT

OK

4.

PERFORM TEST MODE (SIGNAL CHECK) INSPECTION (SPEED SENSOR CIRCUIT)

(a) 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.

Click here 2020 - 2022 MY Corolla Corolla HV [01/2019 - 09/2022]; BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM (for HV Model): TEST MODE PROCEDURE

Chassis > ABS/VSC/TRAC > Utility

Tester Display

Signal Check

OK:

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

NG

INSPECT AND REPAIR MALFUNCTIONING SPEED SENSOR CIRCUIT
OK

5.

PERFORM OPERATION CHECK DRIVING

(a) 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.

(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 TR(A)C operates when attempting to make the drive wheels slip.

OK:

TR(A)C 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 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.
OK

USE SIMULATION METHOD TO CHECK

NG

REPLACE BRAKE BOOSTER WITH MASTER CYLINDER ASSEMBLY