When the engine switch is turned on (IG), check that the ABS warning, BRAKE warning, master caution indicator, and SLIP indicator lights come on for approximately 3 seconds. Make sure that the message on the multi information display changes from "CHECK" to "COMPLETE" for 2 seconds.

HINT:

If the ECU stores any DTCs, the ABS, BRAKE, VSC warning (multi information display and master caution indicator light) lights, and SLIP indicator light come on.

If the indicator remains on or does not come on, proceed to troubleshooting for the light circuits listed below.

Trouble Area	See procedure
ABS warning light circuit	or
BRAKE warning light circuit	or
VSC warning light circuit	or
SLIP indicator light circuit	or

SENSOR SIGNAL CHECK BY TEST MODE (SIGNAL CHECK) (INTELLIGENT TESTER)

NOTICE:

After replacement of the brake actuator assembly and/or yaw rate and acceleration sensor, perform zero point calibration of the yaw rate and acceleration sensor.

HINT:

If the engine switch is turned from on (IG) to on (ACC) or off during Test Mode (signal check), DTCs of the signal check function will be erased.

During Test Mode (signal check), the skid control ECU records all DTCs of the signal check function. By performing the Test Mode (signal check), the codes are erased if a normal condition is confirmed. The remaining codes are the codes where an abnormality was found.

Procedure for Test Mode.

Turn the engine switch off.

Connect the intelligent tester to the DLC3.

Check that the steering wheel is centered and move the shift lever to the P position (A/T) or apply the parking brake (M/T).

Turn the engine switch on (IG).

Set the intelligent tester to Test Mode (select "Signal Check").

HINT:

Refer to the intelligent tester operator's manual for further details.

Check that the ABS warning light and master caution indicator light blink and "VSC TEST MODE" is displayed on the multi information display (Test Mode).

HINT:

If the ABS and VSC warning (multi information display and master caution indicator light) lights do not blink, inspect the TS and CG terminal circuit, and ABS and VSC warning light circuits.

Trouble Area	See procedure
TS and CG terminal circuit
ABS warning light circuit
VSC warning light circuit

Check the ABS sensor.

HINT:

Check that the ABS warning light is blinking in Test Mode and perform the check.

LOST BOOSTER PRESSURE JUDGEMENT CHECK AND MASTER CYLINDER PRESSURE SENSOR ZERO POINT CALIBRATION (INTELLIGENT TESTER)

NOTICE:

Perform the check in the lost booster pressure state (negative pressure in the booster is depressurized).

Turn the engine switch on (IG).

Check that the BRAKE warning light comes on when depressing the brake pedal with a force of 59 N (6 kgf, 13.2 lbf) or more for 1 second or more. (The lost booster pressure state is judged normal.)

Start the engine depressing the brake pedal with a force of 59 N (6 kgf, 13.2 lbf) or more for 1 second or more.

Check that the BRAKE warning light goes off when quickly releasing the brake pedal. (The lost booster pressure state is judged normal.)

Leave the vehicle for 1 second or more. (Master cylinder pressure sensor zero point calibration)

NOTICE:

If you slowly depress the brake pedal or depress it again, master cylinder pressure sensor zero point calibration is not performed normally.

If lost booster pressure judgement check is not completed normally, master cylinder pressure sensor check is not judged.

If recheck is performed after the engine has started, end the Test Mode, transit to the Test Mode again, and release the vacuum in the booster by pumping the brake pedal prior to the recheck.

ACCELERATION SENSOR CHECK (INTELLIGENT TESTER)

Keep the vehicle stationary on a level surface for 1 second or more.

HINT:

Acceleration sensor check can be performed with the master cylinder pressure sensor check below.

MASTER CYLINDER PRESSURE SENSOR CHECK (INTELLIGENT TESTER)

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 of 98 N (10 kgf, 22 lbf) or more for 1 second.

Check that the ABS warning light stays on for 3 seconds.

HINT:

Ensure that the ABS warning light comes on.

While the ABS warning light stays on, continue to depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more.

The ABS warning light comes on for 3 seconds every time brake pedal operation above is performed.

If the check of the master cylinder pressure sensor is not completed, depressing the brake pedal causes further decrease in the negative pressure, making the sensor check difficult to be completed.

If the negative pressure is insufficient, the master cylinder pressure sensor check may not be completed. In this case, run the engine at idle to obtain sufficient negative pressure.

If the brake pedal is strongly depressed when the negative pressure is insufficient, the BRAKE warning light may come on in accordance with the booster pressure control. In this case, run the engine at idle to obtain sufficient negative pressure.

SPEED SENSOR CHECK (INTELLIGENT TESTER)

Check the reverse signal.

Drive the vehicle in reverse for more than 1 second at 2 mph (3 km/h) or more.

HINT:

Drive the vehicle in reverse and check the speed sensor signal. Note that the sensor check cannot be completed if the vehicle speed is 28 mph (45 km/h) or more.

Check the forward signal.

Drive the vehicle straight ahead.

Accelerate the vehicle to a speed of 28 mph (45 km/h) or more for several seconds and check that the ABS warning light goes off.

HINT:

The sensor check may not be completed if the vehicle has its wheels spun.

Stop the vehicle.

NOTICE:

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

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

After the ABS warning light goes off and if the vehicle speed exceeds 50 mph (80 km/h), a signal check code will be stored again. Accelerate or stop the vehicle before the speed reaches 50 mph (80 km/h).

If the signal check has not been completed, the ABS warning light blinks while driving and the ABS system does not operate.

If the vehicle is driven in reverse at 28 mph (45 km/h) or more, the sensor check will not be completed.

HINT:

When the sensor check has been completed, the ABS warning light goes off while driving and blinks in the Test Mode pattern while stationary.

Check the VSC sensor.

Check that the master caution indicator light blinks and "VSC TEST MODE" is displayed on the multi information display, and perform the check.

YAW RATE SENSOR CHECK (INTELLIGENT TESTER)

Check the output of the yaw rate sensor.

Keep the vehicle in a stationary condition on a level surface for 1 second or more.

Move the shift lever from P to the D position (A/T) or release the parking brake (M/T) and drive the vehicle at a speed of approximately 3 mph (5 km/h), and turn the steering wheel either to the left or right 90° or more until the vehicle makes a 180° turn.

Stop the vehicle and move the shift lever to the P position (A/T) or apply the parking brake (M/T). Check that the skid control buzzer sounds for 3 seconds.

HINT:

If the skid control buzzer sounds, the sensor check is completed normally.

If the skid control buzzer does not sound, check the skid control buzzer circuit , then perform the sensor check again.

If the skid control buzzer still does not sound, there is a malfunction in the yaw rate sensor, so check the DTC.

Make a 180° turn. At the end of the turn, the direction of the vehicle should be within 180° +- 5° of its start position.

Do not spin the wheels.

Do not turn the engine switch off while turning.

Do not move the shift lever to the P position (A/T) or do not apply the parking brake (M/T) while turning, but changing in the vehicle speed, stopping, or driving in reverse is possible.

Complete the turn within 20 seconds.

END OF SENSOR CHECK (INTELLIGENT TESTER)

If the sensor check is completed, the ABS warning light blinks (Test Mode) when the vehicle stops and the ABS warning light is off while the vehicle is driven.

NOTICE:

When the yaw rate sensor, acceleration sensor, speed sensor and master cylinder pressure sensor checks are completed, the sensor check is completed.

If the sensor check is not completed, the ABS warning light blinks even while the vehicle is driven and the ABS does not operate.

READ DTC OF SIGNAL CHECK FUNCTION (INTELLIGENT TESTER)

Read the DTC(s) by following the tester screen.

NOTICE:

If only the DTCs are displayed, repair the malfunction area and clear the DTCs.

If the DTCs or Test Mode codes (DTC of signal check function) are displayed, repair the malfunction area, clear the DTCs and perform the Test Mode inspection.

HINT:

See the list of DTC (See procedure "A").

SENSOR SIGNAL CHECK BY TEST MODE (SIGNAL CHECK) (SST CHECK WIRE)

NOTICE:

After replacement of the brake actuator assembly and/or yaw rate and acceleration sensor, perform zero point calibration of the yaw rate and acceleration sensor.

HINT:

If the engine switch is turned from on (IG) to on (ACC) or off during Test Mode (signal check), DTCs of the signal check function will be erased.

Procedure for Test Mode.

Turn the engine switch off.

Check that the steering wheel is centered and move the shift lever to the P position (A/T) or apply the parking brake (M/T).

Using SST, connect terminals TS and CG of the DLC3.

SST
09843-18040

Turn the engine switch on (IG).

Check that the ABS warning light and master caution indicator light blink and "VSC TEST MODE" is displayed on the multi information display (Test Mode).

HINT:

If the ABS and VSC warning (multi information display and master caution indicator light) lights do not blink, inspect the TS and CG terminal circuit, and ABS and VSC warning light circuits.

Trouble Area	See procedure
TS and CG terminal circuit
ABS warning light circuit
VSC warning light circuit

Check the ABS sensor.

HINT:

Check that the ABS warning light is blinking in Test Mode and perform the check.

LOST BOOSTER PRESSURE JUDGEMENT CHECK AND MASTER CYLINDER PRESSURE SENSOR ZERO POINT CALIBRATION (SST CHECK WIRE)

NOTICE:

Perform the check in the lost booster pressure state (negative pressure in the booster is depressurized).

Turn the engine switch on (IG).

Check that the BRAKE warning light comes on when depressing the brake pedal with a force of 59 N (6 kgf, 13.2 lbf) or more for 1 second or more. (The lost booster pressure state is judged normal.)

Start the engine depressing the brake pedal with a force of 59 N (6 kgf, 13.2 lbf) or more for 1 second or more.

Check that the BRAKE warning light goes off when quickly releasing the brake pedal. (The lost booster pressure state is judged normal.)

Leave the vehicle for 1 second or more. (Master cylinder pressure sensor zero point calibration)

NOTICE:

If you slowly depress the brake pedal or depress it again, master cylinder pressure sensor zero point calibration is not performed normally.

If lost booster pressure judgement check is not completed normally, master cylinder pressure sensor check is not judged.

If recheck is performed after the engine has started, end the Test Mode, transit to the Test Mode again, and release the vacuum in the booster by pumping the brake pedal prior to the recheck.

ACCELERATION SENSOR CHECK (SST CHECK WIRE)

Keep the vehicle stationary on a level surface for 1 second or more.

HINT:

Acceleration sensor check can be performed with the master cylinder pressure sensor check below.

MASTER CYLINDER PRESSURE SENSOR CHECK (SST CHECK WIRE)

Check ABS warning light stays on for 3 seconds.

HINT:

Ensure that the ABS warning light comes on.

While the ABS warning light stays on, continue to depress the brake pedal with a force of 98 N (10 kgf, 22 lbf) or more.

The ABS warning light comes on for 3 seconds every time the brake pedal operation above is performed.

If the check of the master cylinder pressure sensor is not completed, depressing the brake pedal causes further decrease in the negative pressure, making the sensor check difficult to be completed.

If the negative pressure is insufficient, the master cylinder pressure sensor check may not be completed. In this case, run the engine at idle to obtain sufficient negative pressure.

SPEED SENSOR CHECK (SST CHECK WIRE)

Check the reverse signal.

Drive the vehicle in reverse for more than 1 second at 2 mph (3 km/h) or more.

HINT:

Drive the vehicle in reverse and check the speed sensor signal. Note that the sensor check cannot be completed if the vehicle speed is 28 mph (45 km/h) or more.

Check the forward signal.

Drive the vehicle straight ahead.

Accelerate the vehicle to a speed of 28 mph (45 km/h) or more for several seconds and check that the ABS warning light goes off.

HINT:

The sensor check may not be completed if the vehicle has its wheels spun.

Stop the vehicle.

NOTICE:

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

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

After the ABS warning light goes off, if vehicle speed exceeds 50 mph (80 km/h), a signal check code will be stored again. Accelerate or stop the vehicle before the speed reaches 50 mph (80 km/h).

If the signal check has not been completed, the ABS warning light blinks while driving and the ABS system does not operate.

If the vehicle is driven in reverse at 28 mph (45 km/h) or more, the sensor check will not be completed.

HINT:

When the sensor check has been completed, the ABS warning light goes off while driving and blinks in the Test Mode pattern while stationary.

Check the VSC sensor.

Check that the master caution indicator light blinks and "VSC TEST MODE" is displayed on the multi information display, and perform the check.

YAW RATE SENSOR CHECK (SST CHECK WIRE)

Check the output of the yaw rate sensor.

Keep the vehicle stationary on a level surface for 1 second or more.

Move the shift lever from P to the D position (A/T) or release the parking brake (M/T) and drive the vehicle at a vehicle speed of approximately 3 mph (5 km/h) and turn the steering wheel either to the left or right 90° or more until the vehicle makes a 180° turn.

Stop the vehicle and move the shift lever to the P position (A/T) or apply the parking brake (M/T). Check that the skid control buzzer sounds for 3 seconds.

HINT:

If the skid control buzzer sounds, the sensor check is completed normally.

If the skid control buzzer does not sound, check the skid control buzzer circuit , then perform the sensor check again.

If the skid control buzzer still does not sound, there is a malfunction in the yaw rate sensor, so check the DTC.

Make a 180° turn. At the end of the turn, the direction of the vehicle should be within 180° +- 5° of its start position.

Do not spin the wheels.

Do not turn the engine switch off while turning.

Do not move the shift lever to the P position (A/T) or do not apply the parking brake (M/T) while turning, but changing in the vehicle speed, stopping, or driving in reverse is possible.

Complete the turn within 20 seconds.

END OF SENSOR CHECK (SST CHECK WIRE)

If the sensor check is completed, the ABS warning light blinks (Test Mode) when the vehicle stops and the ABS warning light is off while the vehicle is driven.

NOTICE:

When the yaw rate sensor, acceleration sensor, speed sensor and master cylinder pressure sensor checks are completed, the sensor check is completed.

If the sensor check is not completed, the ABS warning light blinks even while the vehicle is driven and the ABS does not operate.

READ DTC OF SIGNAL CHECK FUNCTION (SST CHECK WIRE)

Using SST, connect terminals TC and CG of the DLC3.

SST
09843-18040

Count the number of blinks of the ABS warning light and read "DIAG VSC" on the multi information display.

Vehicle Stability Control System (W/O Vdim) - Test Mode Procedure. BRAKE CONTROL. Lexus IS250 IS220d GSE20 ALE20

NOTICE:

If only the DTCs are displayed, repair the malfunction area and clear the DTCs.

If the DTCs or Test Mode codes (DTC of signal check function) are displayed, repair the malfunction area, clear the DTCs and perform the Test Mode inspection.

HINT:

If more than 1 malfunction is detected at the same time, the lowest numbered code will be displayed first.

See the list of DTC (See procedure "A").

After performing the check, disconnect the SST from terminals TS and CG, and TC and CG of the DLC3 and turn the engine switch off.

Turn the engine switch on (IG).

HINT:

If the engine switch is not turned on (IG) after the SST is removed from the DLC3, the previous Test Mode will continue.

If the engine switch is turned on (IG) with terminals TS and CG shorted, the previous Test Mode will continue.

DTC OF TEST MODE (SIGNAL CHECK) FUNCTION (Procedure "A")

ABS sensor:
Code No.	Diagnosis	Trouble Area
C1271/71	Low output signal of front speed sensor RH	Front speed sensor RH Sensor installation Speed sensor rotor
C1272/72	Low output signal of front speed sensor LH	Front speed sensor LH Sensor installation Speed sensor rotor
C1273/73	Low output signal of rear speed sensor RH	Rear speed sensor RH Sensor installation Speed sensor rotor
C1274/74	Low output signal of rear speed sensor LH	Rear speed sensor LH Sensor installation Speed sensor rotor
C1275/75	Abnormal change in output signal of front speed sensor RH	Speed sensor rotor
C1276/76	Abnormal change in output signal of front speed sensor LH	Speed sensor rotor
C1277/77	Abnormal change in output signal of rear speed sensor RH	Speed sensor rotor
C1278/78	Abnormal change in output signal of rear speed sensor LH	Speed sensor rotor
C1279/79	Acceleration sensor output voltage malfunction	Yaw rate and acceleration sensor Sensor installation
C1281/81	Master cylinder pressure sensor output malfunction	Stop light switch Brake pedal load sensing switch Master cylinder pressure sensor

VSC sensor:
Code No.	Diagnosis	Trouble Area
C0371/71	Yaw rate sensor	Yaw rate and acceleration sensor

HINT:

The codes in this table are output only in Test Mode (signal check).

LEXUS IS250, IS220d / GSE20 ALE20

BRAKE CONTROL

Lexus IS250 IS220d GSE20 ALE20

VEHICLE STABILITY CONTROL SYSTEM w/o VDIM