2003 LEXUS LS430 Abs

Fig. 7: ABS & TRACTION Actuator - Traction Control
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Operation description
The skid control ECU detects vehicle's slip condition by receiving signals from the speed sensor
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380003004600520051005700550052004f0056000300480051[gine torque with the ECM,
vehicle position with suspension control ECU via CAN communication, and oil pressure with the
pump and solenoid valve. The SLIP indicator lamp blinks when the system is operating. TRAC
OFF switch stops traction control operation.
e. VSC (Vehicle Stability Control)
The VSC system helps prevent the vehicle from slipping sideways as a result of strong front wheel skid or
stron
g rear wheel skid during cornering.

Fig. 8: ABS & TRACTION Actuator - Vehicle Stability Control
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Operation description
The skid control ECU determines vehicle condition by receiving signals from the speed sensor, yaw rate
and deceleration sensor and steering angle sensor. The skid control ECU controls engine torque with the
ECM, vehicle position with suspension control ECU via CAN communication, and oil pressure with the
pump and solenoid valve. The warning light comes on and the buzzer sounds when the system is
operating.
2.ABS with EBD & BA & TRAC & VSC OPERATION
a. Skid control ECU calculates vehicle stability tendency based on the signal of sensors, speed sensor,
yaw rate and deceleration sensor and steering angle sensor. And it judges whether the control of
engine output torque by electronic control throttle and of wheel brake pressure by brake actuator
will operate or not by the calculation results.
b. The SLIP indicator blinks and the VSC buzzer sounds to inform the driver that the VSC system is
operating. The SLIP indicator also blinks when TRAC is operating, and the operation being
performed is displayed.
3.FAIL SAFE FUNCTION
a. When a failure occurs in the ABS with BA & TRAC & VSC systems, the ABS warning light and
the VSC warning light turns on and the ABS with BA & TRAC & VSC operations are prohibited.
In addition to this, when there is a failure that disables the EBD operation, the brake warning light
also comes on and the EBD operation is prohibited (see FAIL
-SAFE CHART ).
b. If some control is prohibited due to a malfunction during it's operation, that control will be cut off
gradually not to change stability of vehicle suddenly.
4.PRE-COLLISION BRAKE ASSIST SYSTEM (w/ PRE-COLLISION BRAKE ASSIST SYSTEM)

Fig. 9: ABS & EBD & BA Check Sheet
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:
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57004b00480003004500550044004e004800030049004f0058[id is low, the BRAKE warning light
comes on.
b. When the ignition switch is turned to the ON position, check that the ABS warning light, TRAC
OFF indicator light, BRAKE warning light and SLIP indicator light come on for approximately 3
seconds.
HINT:
If the ECU was any stored DTCs, the ABS warning light, "VSC" is displayed on the multi-
information display and TRAC OFF indicator light come on.
If the indicator does not come on, inspect it the bulb is blown out, and also the wire harness
between the skid control ECU and the combination meter.

Fig. 19: Identifying VSC Location
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
If the indicator remains on, proceed to troubleshooting for the light circuit below.
TROUBLE AREA REFERENCE
2.SENSOR SIGNAL CHECK BY TEST MODE
HINT:
If the ignition switch is turned from ON to the ACC or LOCK position during test mode, DTC of
Trouble areaSee Procedure
ABS warning light circuitABS WARNING LIGHT CIRCUIT (REMAINS ON)
BRAKE warning light circuitBRAKE WARNING LIGHT CIRCUIT
TRAC OFF indicator light
circuitTRAC OFF INDICATOR LIGHT, TRAC OFF SWITCH
CIRCUIT
SLIP indicator light circuitSLIP INDICATOR LIGHT CIRCUIT

Fig. 21: ABS Warning Light Blinking Pattern
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
5. Check that the ABS warning light blinking TEST MODE and "VSC Test" is displayed on the
multi-information display.
HINT:
If the ABS warning light and VSC information do not blink, inspect the ABS warning light
circuit and VSC warning information circuit.
TROUBLE AREA REFERENCE
6. Start the engine.
b. DECELERATION SENSOR CHECK
1. Check that the ABS warning lamp is blinking in TEST MODE.
2. Keep the vehicle in the stationar
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110003[
Trouble areaSee Procedure
ABS warning light circuitABS WARNING LIGHT CIRCUIT (DOES NOT
LIGHT UP)
VSC warning information
circuitVSC WARNING LIGHT CIRCUIT (DOES NOT
LIGHT UP)

HINT:
The blinking pattern of the ABS warning lamp and the "VSC Test" display on the multi-
information do not change. When the sensor is normal and in the test mode, if the above conditions
are met, the check is completed.
Fig. 22: Identifying VSC Test Location

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
c. CHECK THE MASTER CYLINDER PRESSURE SENSOR
1. Leaving the vehicle in a stationary condition engine is off and the brake pedal in a free
condition for 1 second. or more, continue to quickly depress the brake pedal with a force of
98 N (10 kgf, 22 lbf) or more for 1 second, or more.
HINT:
At this time, the ABS warnin
g light stays on for 3 seconds.

Fig. 24: Identifying VSC Test Location
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
e. BRAKE PEDAL LOAD SENSING SWITCH CHECK
1. Keep depressing the brake pedal for one second or more with a brake pedal load of
approximately 59 N (6kgf) with the ignition switch in the ON position (engine is off).
2. Check if the brake warning lamp comes on and the ABS motor operating sound can be heard.
HINT:
If rechecking the brake pedal load sensing switch after the engine starts, exit the test mode
and enter the test mode to release the negative pressure in the booster by pumping the brake
pedal.
3. Start the engine and depress the brake pedal with a brake pedal load of approximately 59 N
(6 kgf) or more to check if the brake warning lamp goes off.
f. SPEED SENSOR CHECK
1. Check the ABS warnin
g lamp is blinking in TEST MODE.