2003 LEXUS LS430 warning light

PRECAUTION
SYSTEM NAME AND PAGE REFERENCE
Keep in mind the following points when inspecting the dynamic laser cruise control system.
As there is a limitation to the vehicle-to-vehicle distance controlling capability, do not overly rely on the
dynamic laser cruise control system.
Do not neglect to pay constant attention to the vehicle-to-vehicle distance and the traffic conditions when
using the dynamic laser cruise control system. Decelerate with the brake pedal, or accelerate with the
accelerator pedal, according to the situation, to keep an appropriate distance with the vehicle in front.
When the vehicle in front decelerates rapidly or another vehicle pulls out in front of the vehicle,
decelerating in time to avoid a collision may not be possible without additional braking.
The dynamic laser cruise control system is designed to assist in maintaining an appropriate distance with
the vehicle in front. However, the system alone is not sufficient. It is imperative that the driver pays
attention at all times.
The laser sensor has functions to automatically detect dirt on the sensor face and inform the driver, but it
is not perfect. Keep the sensor face clean.
The dynamic laser cruise control system does not work, or give vehicle-approaching warning, for vehicles
which are stopped or driving at significantly slower speeds. Always pay attention to those other vehicles.
The laser sensor detection area is narrow at close range, so detection of a vehicle pulling out just in front
may be delayed, or a motorcycle running on the side of the same lane may not be detected. The distance
to the vehicle in front may not be maintained properly due to these reasons.
Even if ACCEL is operated to increase the set vehicle speed, the vehicle does not accelerate because the
speed is controlled in accordance with the speed of the vehicle in front while driving with the vehicle-to-
vehicle distance control mode on (follow-up cruising). However, as the set vehicle speed has been
increased by ACCEL operation, the vehicle keeps accelerating when there is no vehicle in front. Check
the set speed with the set vehicle speed indication on the display.
The controlled vehicle distance may be shorter than the set vehicle distance when cruising on a long
downhill road.
Push the cruise control main switch ON-OFF button off and reset the cruise control if the master warning
light comes on, the CRUISE main indicator light blinks, and the fail indication is shown on the display
with a "pong" sound during dynamic laser cruise control operation.
System NameSee Procedure
Front Power Seat Control SystemINITIALIZATION

Fig. 27: Signal Waveform Graph (Waveform 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.DIAGNOSIS FUNCTION
a. The diagnosis function makes the master warning light and the multi-information display come on,
and the CRUISE main indicator light blinks as shown in the illustration. When a malfunction
occurs in the dynamic laser cruise control system, the DTCs are stored in the ECM.

Fig. 28: Identifying CRUISE Main Indicator Light And Master Warning Light
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig. 33: Connecting Hand-Held Tester To DLC3
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.Constant speed control mode and vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
clears the stored vehicle speed in the ECM and cancels the dynamic laser cruise control operation.
Fig. 34: Identifying CRUISE Main Indicator Light And Master Warning Light

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 35: Fail
-Safe Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.Only in the vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
clears the stored vehicle speed in the ECM and cancels the dynamic laser cruise control operation.
Fig. 36: Identifying CRUISE Main Indicator Light And Master Warning Light

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 37: Fail
-Safe Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
3.Only in the vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
maintains the stored vehicle speed in the ECM and cancels the d
ynamic laser cruise control operation.

Fig. 38: Identifying Master Warning Light
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 39: Fail
-Safe Chart (1 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
4.Constant speed control mode and vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
clears the stored vehicle speed and cancels the dynamic laser cruise control operation.
HINT:
In the vehicle-to-vehicle distance control mode, the stored vehicle speed in the ECM is maintained.
Fig. 40: Fail
-Safe Chart (2 Of 2)

HINT:
If a trouble code is displayed during the DTC check, check the circuit listed for that code. For details of each
code, refer to the DTC chart below.
DIAGNOSTIC TROUBLE CODE CHART
L-CRUISE DISPGraphic area is ON / OFF((1))
L-CRS CHECK IND"CHECK CRUISE SYSTEM" indicator is ON / OFF-
L-CRS READY IND"RADAR READY" indicator is ON / OFF-
(1)The entire graphic area in the combination meter will light up.
DTCDescription
DTC P0500, DTC
P0503
VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION
DTC P0571STOP LIGHT SWITCH CIRCUIT MALFUNCTION
DTC P0607INPUT SIGNAL CIRCUIT MALFUNCTION
DTC P1615, DTC
U1101
COMMUNICATION ERROR FROM DISTANCE CONTROL ECU TO
ECM
DTC P1616, DTC
U0100
COMMUNICATION ERROR FROM ECM TO DISTANCE CONTROL
ECU
DTC P1617DISTANCE CONTROL ECU MALFUNCTION
DTC P1630, DTC
U0122
COMMUNICATION ERROR FROM VSC TO ECM
DTC P1631, DTC
U0100
COMMUNICATION ERROR FROM ECM TO VSC
DTC P1575WARNING BUZZER MALFUNCTION
DTC P1578BRAKE SYSTEM MALFUNCTION
DTC U0235LOST COMMUNICATION WITH CRUISE CONTROL FRONT
DISTANCE RANGE SENSOR
DTC U1102LOST COMMUNICATION WITH RADAR SENSOR
DTC P1570RADAR SENSOR MALFUNCTION
DTC P1572IMPROPER AIMING OF RADAR SENSOR BEAM AXIS
DTC U0126LOST COMMUNICATION WITH STEERING ANGLE SENSOR MODULE
DTC U0123LOST COMMUNICATION WITH YAW RATE SENSOR MODULE

Fig. 53: DTC P1631 And U0100 Problem Symptom Diagnostic Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
HINT:
This circuit uses CAN for communication. Therefore, if there are any malfunctions in the communication
circuit, one or more DTCs in the CAN communication system is/are output.
1.GO TO CAN COMMUNICATION SYSTEM (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
CIRCUIT DESCRIPTION
The ABS & traction actuator assy (skid control ECU) receives the alarm demand signal from the ECM and
operates the skid control buzzer.
The buzzer sounds to warn that the distance between the vehicle in front and your own vehicle is shortening.
Fig. 54: DTC P1575 Problem Symptom Diagnostic
Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
If the vehicle ahead in the same lane significantly decreases its speed or another vehicle pulls in front of your
own vehicle, adequate deceleration cannot be applied and the vehicle-to-vehicle distance will shorten. At this
time, the s
ystem sounds the buzzer and the master warning light blinks to inform the driver.