2003 LEXUS LS430 sensor

indicator light is on), and the vehicle speed is within the set speed range (between the low and high
speed limits).
b. COAST CONTROL
The ECM makes the cruise control demanding throttle opening angle zero degrees and decelerates
the vehicle (the throttle valve is not fully closed due to idle speed control, etc.) when SET/COAST
on the cruise control main switch is pressed and held while the cruise control system is in
operation. Vehicle speed, when the cruise control main switch is released from SET/COAST, is
stored and constant speed control is maintained.
c. TAP-DOWN CONTROL
When tapping down on the cruise control main switch to SET/COAST (for approximately 0.5
second) while the cruise control system is in operation, the stored vehicle speed decreases each
time by approximately 1.6 km/h (1.0 mph). However, when the difference between the driving and
the stored vehicle speed is more than 5 km/h (approximately 3.1 mph), the vehicle speed, when the
cruise control main switch is released from SET/COAST, will be stored and constant speed control
is maintained.
d. ACCELERATION CONTROL
The throttle valve motor of the throttle position sensor and motor is instructed by the ECM to open
<0057004b0048000300590044004f005900480003005a004b00480051000300350028003600380030002800120024002600260028002f00030052005100030057004b00480003004600550058004c005600480003004600520051005700550052004f000300
500044004c005100030056005a004c00570046004b0003004c[s pressed and held while the
cruise control system is in operation. Vehicle speed, when the cruise control main switch is
released from RESUME/ACCEL, is stored and the vehicle is controlled at a constant speed.
e. TAP-UP CONTROL
When tapping up on the cruise control main switch to RESUME/ACCEL (for approximately 0.5
second) while the cruise control system is in operation, the stored vehicle speed increases each time
by approximately 1.6 km/h (1.0 mph). However, when the difference between the driving and the
stored vehicle speed is more than 5 km/h (approximately 3.1 mph), the stored vehicle speed will not
be changed.
f. RESUME CONTROL
If cruise control operation was cancelled with the stop lamp switch or the CANCEL switch, and if
driving speed is within the limit range, pushing the cruise control main switch to
RESUME/ACCEL restores vehicle speed memorized at the time of cancellation, and maintains
constant speed control.
g. MANUAL CANCEL CONTROL
Doing any of the following cancels the cruise control system while in operation. (The stored vehicle
speed in the ECM is maintained.)
Depressing the brake pedal

TROUBLE CODE (GO TO STEP 8)
NORMAL SYSTEM CODE (GO TO STEP 9)
8.(SEE DIAGNOSTIC TROUBLE CODE CHART
)
GO TO STEP 12
9.PROBLEM SYMPTOM SIMULATION
SYMPTOM DOES NOT OCCUR (GO TO STEP 10)
SYMPTOM OCCURS (GO TO STEP 11)
10.SYMPTOM SIMULATION (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
11.(SEE PROBLEM SYMPTOMS TABLE
)
12.CIRCUIT INSPECTION (SEE DTC P0500 VEHICLE SPEED SENSOR CIRCUIT
MALFUNCTION, DTC P0503 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION -
DIAGNOSIS CIRCUIT
)
13.(SEE TERMINALS OF ECM
)
14.IDENTIFICATION OF PROBLEM
15.REPAIR OR REPLACE
16.CONFIRMATION TEST
END

If a malfunction occurs in the vehicle speed sensors, stop lamp switch assy, or other related parts during
cruise control driving, the ECM actuates AUTO CANCEL of the cruise control and then the CRUISE
main indicator light starts to blink, informing the driver of the malfunction. At the same time, data of the
malfunction is stored as a diagnostic trouble code (DTC).
Fig. 14: Identifying Blinking Pattern Of CRUISE Main Indicator Light

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.DTC CHECK
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Read the DTCs on the tester screen.
2.DTC CLEAR

The ignition switch must be turned to the ON position to proceed ACTIVE TEST using the hand-held
tester.
ACTIVE TEST DETAIL (COMBINATION METER ASSY)
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 chart.
DIAGNOSTIC TROUBLE CODE CHART
Fig. 17: Diagnostic Trouble Code Information Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
CIRCUIT DESCRIPTION
See CIRCUIT DESCRIPTION
.
ItemVehicle Condition / Test DetailsDiagnostic Note
CRUISE INDIC"CRUISE" indicator is ON / OFF-
DTCDescription
DTC P0500 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION
DTC P0503 VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION
DTC P0571 STOP LIGHT SWITCH CIRCUIT MALFUNCTION
DTC P0607 INPUT SIGNAL CIRCUIT MALFUNCTION

This DTC indicates the internal abnormalities of the ECM.
DTC P0607 PROBLEM SYMPTOM DIAGNOSTIC
HINT:
The ECM receives signals from each sensor to control all the functions of the cruise control with the
microcomputer.
When a trouble code is detected, fail-safe remains on until the ignition switch is turned off.
INSPECTION PROCEDURE
1.REPLACE ECM (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The cruise control main switch operates seven functions: SET, COAST, TAP-DOWN, RESUME, ACCEL,
TAP-UP, and CANCEL. The SET, TAP-DOWN and COAST functions, and the RESUME, TAP-UP and
ACCEL functions are operated with the same switch respectively. The cruise control main switch is an
automatic return type switch which turns on only while operating it in each arrow direction and turns off after
releasing it. The internal contact point of the cruise control main switch is turned on with the switch operation.
Then the ECM reads the resistance value that has been changed by the switch operation to control SET,
COAST, RESUME, ACCEL and CANCEL.
WIRING DIAGRAM
DTC No.Detection ItemTrouble Area
P0607The ECM has a supervisory CPU and a control ECU inside. When
each input STP signal is different for 0.15 sec. or more, this trouble
code is output. This trouble code is output after 0.4 sec. has passed
from the time the cruise cancel input signal (STP input) is input into
the ECM.ECM

3. With the brake pedal depressed, push the cruise control main switch to RES/ACC 3 times within 3
seconds. Check that the VSC buzzer sounds at this time.
REPLACEMENT
1.SEPARATE BATTERY NEGATIVE TERMINAL
2.REMOVE ENGINE UNDER COVER NO. 1 (See REPLACEMENT
)
3.REMOVE FRONT WHEEL OPENING EXTENSION PAD LH (See REPLACEMENT
)
4.REMOVE FRONT FENDER LINER LH (See REPLACEMENT
)
5.REMOVE FRONT WHEEL OPENING EXTENSION PAD RH (See REPLACEMENT
)
6.REMOVE FRONT FENDER LINER RH (See REPLACEMENT
)
7.REMOVE FRONT BUMPER COVER (See step 5 in REPLACEMENT
)
8.REMOVE FRONT BUMPER REINFORCEMENT SUB-ASSY (See step 9 in REPLACEMENT
)
9.REMOVE LASER SENSOR
a. Disconnect the connector and remove the laser sensor.

Fig. 2: Removing Laser Sensor
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
10.INSTALL LASER SENSOR
11.INSTALL FRONT BUMPER REINFORCEMENT SUB-ASSY (See step 25 in REPLACEMENT
)
12.ADJUST FOG LIGHT AIM (See ADJUSTMENT
)
13.CHECK FOG LIGHT AIM
14.ADJUST LASER SENSOR (See ADJUSTMENT
)
ADJUSTMENT

HINT:
There is a limitation on laser optical axis adjustment.
Since the laser sensor is installed in the bumper reinforcement, it is important that the laser sensor,
bumper reinforcement, and other related parts are installed properly.
When the sensor is removed from the vehicle for trouble diagnosis or repair, it is necessary to adjust the
laser optical axis after the operation.
1.ADJUST LASER SENSOR
a. Preparation for adjusting the laser optical axis
1. Adjust the tire pressure properly (see INSPECTION
).
2. Luggage in the vehicle, such as in the trunk, should be unloaded.
3. Clean the light-luminous and light-receiving portions of the laser sensor.
HINT:
Prepare a 10 m (32.81 ft) string, with a sharp-pointed weight (plumb bob), and a 5 m (16.41 ft) tape
measure.