Lexus ES: Test Mode Procedure

Lexus ES (XZ10) Service Manual / Brake / Brake Control / Dynamic Control Systems / Electronically Controlled Brake System (for Hv Model) / 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 (No. 3 combination 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.

Trouble Area	See Procedure
ABS warning light circuit (Remains on)
ABS warning light circuit (Does not come on)
Brake warning light / red (malfunction) circuit (Remains on)
Brake warning light / red (malfunction) circuit (Does not come on)
Brake warning light / yellow (minor malfunction) circuit (Remains on)
Brake warning light / yellow (minor malfunction) circuit (Does not come on)
VSC OFF indicator light circuit (Remains on)
VSC OFF indicator light circuit (Does not come on)
Slip indicator light circuit (Remains on)
Slip indicator light circuit (Does not come on)
Brake hold standby indicator light circuit
Brake hold operated indicator light circuit

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 forward recognition camera 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 (No. 3 combination 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.

Chassis > ABS/VSC/TRAC > Utility

Tester Display
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 U023A87 may be stored. If DTC U023A87 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.

(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 (No. 3 Combination 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 (No. 3 combination switch assembly).

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

(4) Press the brake hold switch (No. 3 combination 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

Item Name	Range	Judgment Description	Trouble Area
Output Signal of Front Speed Sensor RH	Incomplete/complete	Check for foreign matter Check the gap between the sensor and rotor	Open or short in speed sensor Open or short in wire harness Improperly connected connector, deformation or corrosion of terminals Sensor installation Front speed sensor rotor RH (front axle hub sub-assembly RH)
Output Signal of Front Speed Sensor LH	Incomplete/complete	Check for foreign matter Check the gap between the sensor and rotor	Open or short in speed sensor Open or short in wire harness Improperly connected connector, deformation or corrosion of terminals Sensor installation Front speed sensor rotor LH (front axle hub sub-assembly LH)
Output Signal of Rear Speed Sensor RH	Incomplete/complete	Check for foreign matter Check the gap between the sensor and rotor	Open or short in speed sensor Open or short in wire harness Improperly connected connector, deformation or corrosion of terminals Sensor installation Rear speed sensor rotor RH (rear axle hub and bearing assembly RH)
Output Signal of Rear Speed Sensor LH	Incomplete/complete	Check for foreign matter Check the gap between the sensor and rotor	Open or short in speed sensor Open or short in wire harness Improperly connected connector, deformation or corrosion of terminals Sensor installation Rear speed sensor rotor LH (rear axle hub and bearing assembly LH)
Change in Output Signal of Front Speed Sensor RH	Incomplete/complete	Check the stability of the sensor output waveform	Front speed sensor RH Front speed sensor rotor RH (front axle hub sub-assembly RH)
Change in Output Signal of Front Speed Sensor LH	Incomplete/complete	Check the stability of the sensor output waveform	Front speed sensor LH Front speed sensor rotor LH (front axle hub sub-assembly LH)
Change in Output Signal of Rear Speed Sensor RH	Incomplete/complete	Check the stability of the sensor output waveform	Rear speed sensor RH (rear axle hub and bearing assembly RH) Rear speed sensor rotor RH (rear axle hub and bearing assembly RH)
Change in Output Signal of Rear Speed Sensor LH	Incomplete/complete	Check the stability of the sensor output waveform	Rear speed sensor LH (rear axle hub and bearing assembly LH) Rear speed sensor rotor LH (rear axle hub and bearing assembly LH)
Output Voltage in Deceleration Sensor	Incomplete/complete	Check the acceleration sensor output voltage	Zero point calibration undone Improperly connected connector, deformation or corrosion of terminals Acceleration sensor (airbag ECU assembly) internal stuck malfunction Acceleration sensor (airbag ECU assembly) installed improperly
Memory of System Information	Incomplete/complete	Check stored system information (skid control ECU (brake booster with master cylinder assembly)) against vehicle specification	Hybrid vehicle control ECU incorrectly installed Main body ECU (multiplex network body ECU) incorrectly installed Skid control ECU (brake booster with master cylinder assembly) CAN communication between hybrid vehicle control ECU or main body ECU (multiplex network body ECU) and skid control ECU (brake booster with master cylinder assembly)
Output in Master Cylinder Pressure Sensor	Incomplete/complete	Check that the sensitivity of the reaction force pressure sensor is normal	Open or short in reaction force pressure sensor Open or short in stop light switch assembly Stop light switch assembly stuck off malfunction
Learning of Stroke Sensor Zero Point	Incomplete/complete	Check the stroke sensor zero point output value	Brake pedal stroke sensor zero point calibration incomplete Open or short in wire harness Improperly connected connector, deformation or corrosion of terminals Brake pedal stroke sensor assembly

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