LEXUS LS430 2003 Factory User Guide

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)

If a collision (front collision) is determined to be unavoidable, the pre-collision brake assist system
receives the brake assist standby signal from the distance control ECU and enters brake assist standby
mode.
If the STP signal is input, the pre-collision brake assist system improves deceleration performance by
increasing pressure according to the amount of brake pedal effort.
The hand-held tester can be used at step 5, 8, 11, 14
1.Vehicle Brought to Workshop
2.(SEE CUSTOMER PROBLEM ANALYSIS CHECK
)
3.Check MULTIPLEX COMMUNICATION SYSTEM (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
DTC is output: Check MULTIPLEX COMMUNICATION circuit (SEE HOW TO PROCEED
WITH TROUBLESHOOTING )
There is no output: Go to step 4
4.(SEE CHECK CAN BUS LINE
)
DTC is output: Check CAN COMMUNICATION circuit (SEE SKID CONTROL ECU
COMMUNICATION STOP MODE )
There is no output: Go to step 5
5.Check and Clear DTCs (SEE DTC CHECK/CLEAR
)
6.Problem Symptom Confirmation
Symptom does not occur: Go to step 7
Symptom occurs: Go to step 8
7.Symptom Simulation (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
8.(SEE DTC CHECK/CLEAR
)
There is no output: Go to step 9
There is output: Go to step 10
9.(SEE PROBLEM SYMPTOMS TABLE
)
Check for fluid leakage and Go to step 10

10.(SEE DIAGNOSTIC TROUBLE CODE CHART )
11.Circuit Inspection (SEE DTC C0200/31 RIGHT FRONT SPEED SENSOR, DTC C0205/32 LEFT
FRONT SPEED SENSOR to TS AND CG TERMINAL CIRCUIT )
12.Identification of Problem
13.Repair
14.Confirmation Test
End

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

Fig. 10: TRAC & VSC Check Sheet

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.CHECK FOR INTERMITTENT PROBLEMS
HINT:
A momentary interruption (open circuit) in the connectors and/or wire harness between the sensors and ECUs
can be detected in the ECU data monitor function of the hand-held tester.
a. Turn the ignition switch off and connect the hand-held tester to the DLC3.
b. Turn the ignition switch on. Follow the on-screen directions on the hand-held tester to display the DATA
LIST and select areas where momentary interruption should be monitored.
HINT:
A momentary interruption (open circuit) cannot be detected for 3 seconds after the ignition switch is
turned on (initial check).

Fig. 11: Connecting Hand-Held Tester To DLC3
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
MEASUREMENT ITEM / RANGE DESCRIPTION
ItemMeasurement Item / Range (Display)Normal ConditionDiagnostic Note
SPD SEN FRFR speed sensor open detection / OPEN
or NORMALOPEN: Momentary
interruption-
SPD SEN FLFL speed sensor open detection / OPEN
or NORMALOPEN: Momentary
interruption-
SPD SEN RRRR speed sensor open detection / OPEN
or NORMALOPEN: Momentary
interruption-
SPD SEN RLRL speed sensor open detection / OPEN
or NORMALOPEN: Momentary
interruption-
YAWRATE SENYaw rate sensor open detectionOPEN: Momentary
interruption-
DECELE SENG sensor open detectionOPEN: Momentary
interruption-
STEERING SENSteering sensor open detectionOPEN: Momentary
interruption-
M/C SEN 1Master Cylinder pressure sensor 1 open
detectionOPEN: Momentary
interruption-
EFI COMEFI communication open detectionOPEN: Momentary
interruption-

Fig. 12: Harness Signal Blinking Pattern
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
If the hand-held tester's status remains open, check the continuity between the ECU and the
sensors, or between ECUs.
The OPEN display on the hand-held tester remains on for 1 second after the harness signal changes
from momentary interruption (open circuit) to normal condition.
c. While observing the screen, gently jiggle the connector or wire harness between the ECU and sensors, or
between ECUs.
Result: OPEN-screen display does not change.
HINT:
The connector and/or wire harness will be in momentary interruption (open circuit) if the chart fluctuates.
Repair or replace connector and/or wire harness as one of them is fault
y.

Fig. 13: Inspecting Connector And/Or Wire Harness
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.DESCRIPTION
a. After replacin
g the VSC relevant components or performing "Front wheel alignment adjustment",