Toyota Avalon (XX50): Test Mode Procedure. TRAC does not Operate. Vehicle Control History

Test Mode Procedure

TEST MODE PROCEDURE

WARNING LIGHT AND INDICATOR LIGHT INITIAL CHECK

(a) When the power switch is turned on (IG), check that the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction), VSC OFF indicator, slip indicator, brake hold standby indicator and brake hold operated indicator lights all come on approximately 3 seconds.

HINT:

• When the brake fluid level is low, the brake warning light / red (malfunction) comes on.
• If the skid control ECU (brake booster with master cylinder assembly) stores any DTCs, the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights will come on. Also, in this state, if the vehicle is under the following conditions and the brake hold switch (electric parking brake switch assembly) is turned on, the brake hold operated indicator light blinks.
  • Vehicle Conditions:
    1. The driver side door is closed.
    2. The driver side seat belt is fastened.
• If any of the indicators remains on or does not come on, proceed to troubleshooting for the light circuits listed below.

SENSOR CHECK USING TEST MODE (SIGNAL CHECK)

NOTICE:

Before performing the master cylinder pressure sensor check, perform linear solenoid valve offset learning and ABS holding solenoid valve learning.

HINT:

• Signals related to the electronically controlled brake system can be inspected by performing a Test Mode (Signal Check) inspection. During the inspection, the display of items determined normal by the skid control ECU (brake booster with master cylinder assembly) changes from incomplete to complete.
• During Test Mode (Signal Check), the VSC system does not operate regardless of whether the system is normal or a malfunction is detected.
• If a sensor is malfunctioning, ABS does not operate and the ABS warning, brake warning / yellow (minor malfunction) and slip indicator lights illuminate.
• When entering Test Mode (Signal Check), the skid control ECU (brake booster with master cylinder assembly) communicates with the driving support ECU assembly to judge whether the vehicle is equipped with the pre-collision system. Therefore, do not exit Test Mode (Signal Check) within 5 seconds of entering Test Mode (Signal Check).
• Even during Test Mode (Signal Check), 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 turned on, the brake hold operated indicator light blinks.
  • Vehicle Conditions:
    1. The driver side door is closed.
    2. The driver side seat belt is fastened.

(a) Procedure to Enter Test Mode (Signal Check)

(1) Turn the power switch off.

(2) Check that the steering wheel is centered.

(3) Check that the shift lever is in P.

(4) Connect the Techstream to the DLC3.

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

(6) Turn the Techstream on.

(7) Switch the skid control ECU (brake booster with master cylinder assembly) to Test Mode (Signal Check) using the Techstream. Enter the following menus: Chassis / ABS/VSC/TRAC / Utility / Signal Check.

HINT:

Do not exit Test Mode (Signal Check) within 5 seconds of entering Test Mode (Signal Check). If Test Mode (Signal Check) is exited within 5 seconds of entering Test Mode (Signal Check), DTC U1104 may be stored. If DTC U1104 is output after exiting Test Mode (Signal Check), enter Test Mode (Signal Check) again, wait at least 5 seconds, then recheck for DTCs.

(b) Test Mode (Signal Check) Display Check

(1) Check that the ABS warning, brake warning / yellow (minor malfunction) and slip indicator lights come on for several seconds and then blink in the Test Mode pattern.

HINT:

If the ABS warning light, brake warning light / yellow (minor malfunction) or slip indicator light remains illuminated or does not illuminate when Test Mode (Signal Check) is entered, a component or wire harness may be malfunctioning.

(c) Acceleration Sensor Check

(1) Keep the vehicle stationary on a level surface for 2 seconds or more.

HINT:

• The ABS warning light remains blinking.
• If the acceleration sensor is normal and the above step is performed when Test Mode (Signal Check) is entered, the acceleration sensor check will complete normally.
• The acceleration sensor check can be performed by following the master cylinder pressure sensor check procedure below.

(d) Master Cylinder Pressure Sensor Check

NOTICE:

Before performing the master cylinder pressure sensor check, perform linear solenoid valve offset learning and ABS holding solenoid valve learning.

(1) Leave the vehicle in a stationary condition and release the brake pedal for 1 second or more, and quickly and continuously depress the brake pedal with a force greater than 98 N (10 kgf, 22.0 lbf) for 1 second.

(2) Check that the ABS warning light remains on for 3 seconds.

HINT:

• Confirm that the ABS warning light comes on.
• While the ABS warning light remains on, continue to depress the brake pedal with a force of 98 N (10 kgf, 22.0 lbf) or more.
• The ABS warning light comes on for 3 seconds every time the preceding brake pedal operation is performed.

(e) Speed Sensor Check

NOTICE:

Before performing the speed sensor check, complete the acceleration sensor and master cylinder pressure sensor checks.

(1) With the steering wheel held straight, accelerate the vehicle to a speed of 45 km/h (28 mph) or more without spinning the wheels.

NOTICE:

The speed sensor check may not complete if the speed sensor check is started while turning the steering wheel or spinning the wheels.

(2) Check that the ABS warning light goes off.

NOTICE:

If the sensor check has not completed, the ABS warning light will blink while the vehicle is being driven and the ABS will not operate.

(3) Stop the vehicle.

(f) VSC OFF Switch Check

(1) Press the VSC OFF switch.

(2) Check that the VSC OFF indicator light comes on.

(3) Press the VSC OFF switch again.

(4) Check that the VSC OFF indicator light turns off.

(g) Brake Hold Switch (Electric Parking Brake Switch Assembly) Check

HINT:

Perform the check with the system in a normal condition.

(1) Make sure the following conditions are met:

• The driver side door is closed.
• The driver side seat belt is fastened.

(2) Press the brake hold switch (electric parking brake switch assembly).

(3) Check that the brake hold standby indicator light comes on.

(4) Press the brake hold switch (electric parking brake switch assembly) again.

(5) Check that the brake hold standby indicator light turns off.

(h) End of Sensor Check

(1) When the sensor checks have completed, the ABS warning light goes off while the vehicle is being driven, and blinks in the Test Mode pattern while the vehicle is stopped.

NOTICE:

• When the acceleration sensor, speed sensor and master cylinder pressure sensor checks are complete, the sensor check is complete.
• If the sensor checks have not completed, the ABS warning light will remain blinking while the vehicle is being driven, and the ABS will not operate.
• If any malfunctions are detected during Test Mode (Signal Check), the ABS warning light remains illuminated.
• If any DTCs are output or if Test Mode (Signal Check) items do not complete even after repeated attempts, repair or replace the malfunctioning part.

(i) End of Test Mode (Signal Check)

(1) Turn the power switch off and disconnect the Techstream.

(j) Test Mode (Signal Check) Inspection Item Chart

TRAC does not Operate

DESCRIPTION

When ABS, TRAC 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 TRAC 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, 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 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".

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PROCEDURE

(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 when TRAC did not operate.

OK:

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

HINT:

When the multi-information display in the combination meter assembly displays "Traction Control Turned Off", TRAC does not operate.

OK

END

NG

(a) Clear the DTCs.

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(b) Turn the power switch off.

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

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

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B

REPAIR CIRCUITS INDICATED BY OUTPUT DTCS

A

(a) Operate the VSC OFF switch 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

(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.

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OK:

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

NG

INSPECT AND REPAIR MALFUNCTIONING SPEED SENSOR CIRCUIT

OK

(a) Operate the VSC OFF switch 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 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

Vehicle Control History

VEHICLE CONTROL HISTORY

VEHICLE CONTROL HISTORY

HINT:

A part of the control history can be confirmed using the vehicle control history.

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