LEXUS LS430 2003 Factory Repair Manual

Fig. 9: Customer Problem Analysis Check Sheet
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1.PROBLEM SYMPTOM CONFIRMATION
HINT:

The dynamic radar cruise control system has two cruise control modes: the constant speed control mode
and vehicle-to-vehicle distance control mode.
The vehicle-to-vehicle distance control mode is always selected when starting up the dynamic radar
cruise control system.
Operation of the constant speed control mode is the same as that for the conventional type cruise
control system.
a. Inspect the SET function.
1. Push the ON-OFF button on.
2. Drive at the required speed (45 km/h (28 mph) or higher).
3. Push the cruise control main switch to SET/COAST.
4. After releasing the switch, check that the vehicle cruises at the set speed.
Fig. 10: Inspecting SET Function

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b. Inspect the ACCEL function.
1. Push the ON-OFF button on.
2. Drive at the required speed (45 km/h (28 mph) or higher).
3. Push the cruise control main switch to SET/COAST.
4. Check that vehicle speed increases while the cruise control main switch is pushed to

RES/ACC, and that the vehicle cruises at the newly set speed when the switch is released.
5. Momentarily push the cruise control main switch to RES/ACC and then immediately release
it. Check that vehicle speed increases (*1) (Tap-up function).
*1: Constant speed control mode: increases by 1.6km/h (1.0 mph), Vehicle-to-vehicle
distance control mode: increases by 5km/h (5mph)
Fig. 11: Inspecting ACCEL Function

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c. Inspect the COAST function.
1. Push the ON-OFF button on.
2. Drive at the required speed (45 km/h (28 mph) or higher).
3. Push the cruise control main switch to SET/COAST.
4. Check that vehicle speed decreases while the cruise control main switch is pushed to
SET/COAST, and the vehicle cruises at the newl
y set speed when the switch is released.

Fig. 12: Inspecting COAST Function
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5. Momentarily push the cruise control main switch to SET/COAST, and then immediately
release it. Check that vehicle speed decreases (*1) (Tap-down function).
*1: Constant speed control mode: decreases by 1.6km/h (1.0 mph), Vehicle-to-vehicle
distance control mode: decreases by 5km/h (5mph)
d. Inspect the CANCEL function.
1. Push the ON-OFF button on.
2. Drive at the required speed (45 km/h (28 mph) or higher).
3. Push the cruise control main switch to SET/COAST.
4. When doing one of the following, check that the cruise control system is cancelled and that
the normal driving mode is reset.
Depressing the brake pedal
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57004b000f000300180057004b000f00030044005100470003[4th gears)
Pushing the ON-OFF button off
Pulling the cruise control main switch to CANCEL

Fig. 13: Inspecting CANCEL Function
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e. Inspect the RES (RESUME) function.
1. Push the ON-OFF button on.
2. Drive at the required speed (40 km/h (25 mph) or higher).
3. Push the cruise control main switch to SET/COAST.
4. When doing one of the following, check that the cruise control system is cancelled and that
the normal driving mode is reset.
Depressing the brake pedal
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57004b000f000300180057004b000f00030044005100470003[4th gears)
Pulling the cruise control main switch to CANCEL
5. After pushing the cruise control main switch to RES/ACC at a driving speed of more than 40
km/h (25 mph), check that the vehicle restores the speed prior to the cancellation.
HINT:
RESUME function (in the Vehicle-to-vehicle Distance Control Mode only)
The stored vehicle speed is retained even if vehicle speed goes below 40 km/h (25 mph) once. The
previously stored vehicle speed can be resumed by pushing the cruise control main switch to RES/ACC
when vehicle speed returned to approximately 40 km/h (25 mph) or more.

Fig. 14: Inspecting RES (RESUME) Function
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1.INPUT SIGNAL CHECK
a. Connect the hand-held tester to the DLC3.
b. Check the cruise control main switch using the DATA LIST function in the hand-held tester (ON-
OFF, CANCEL, SET/COAST, RES/ACC, and MODE).

Fig. 15: Identifying Cruise Control Main Switch
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2.INSPECT MODE SWITCH
a. Turn the ignition switch to the ON position.
HINT:
Dynamic radar cruise system is in the default mode.
b. After pushing the ON-OFF button on, push the cruise control main switch to MODE for at least 1
second without any other control. Make sure that only "NORM." and nothing else is indicated on
the display.

Fig. 16: Inspecting Mode Switch
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HINT:
If the system cannot switch to the constant speed control mode, push the ON-OFF button off once, and
perform the same procedures as shown above. If a malfunction is still detected in the system, start the
en
gine again and perform the above procedure.

Fig. 17: [Display NORM]
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3.INSPECT STEERING PAD SWITCH ASSY
a. Turn the ignition switch to the ON position.
b. Push on the ON-OFF button of the cruise control main switch.
c. Push on the distance control switch (DISP2) of the steering pad switch.
d. Check that the indication of vehicle-to-vehicle distance, which is shown in the multi-information
displa
y on the combination meter, changes from "LONG", "MIDDLE" to "SHORT" in that order.

Fig. 18: Multi-Information Display Chart On Combination Meter
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HINT:
The indication is immediately set to "LONG" each time the engine is started.
If a normal system code is displayed during the DTC check but the problem still occurs, check the suspected
areas for each problem symptom in the order given in the table below and proceed to the relevant
troubleshooting page.
HINT:
Inspect the "Fuse" and "Relay" before confirming the suspected areas as shown in the Fig. 19
below. Inspect
each suspected area for the correspondin
g symptom in numerical order.