2003 LEXUS LS430 Head

HVAC DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
LIGHTING SYSTEM DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION
SENSOR/SWITCH "D"/"E" VOLTAGE
CORRELATION
DTC P2121 THROTTLE/PEDAL POSITION
SENSOR/SWITCH "D" CIRCUIT
RANGE/PERFORMANCE
DTC U0001 HIGH SPEED CAN COMMUNICATION
CIRCUIT
DTCDescription
DTC B1411 ROOM TEMPERATURE SENSOR CIRCUIT
DTC B1412 AMBIENT TEMPERATURE SENSOR CIRCUIT
DTC B1413 EVAPORATOR TEMPERATURE SENSOR CIRCUIT
DTC B1415 AIR DUCT SENSOR CIRCUIT (DRIVER SIDE)
DTC B1416 AIR DUCT SENSOR CIRCUIT (PASSENGER SIDE)
DTC B1418 EMISSION GAS SENSOR CIRCUIT
DTC B1421 SOLAR SENSOR CIRCUIT (PASSENGER SIDE)
DTC B1423 PRESSURE SWITCH CIRCUIT
DTC B1424 SOLAR SENSOR CIRCUIT (DRIVER SIDE)
DTC B1428 REAR SOLAR SENSOR CIRCUIT
DTC B1432 AIR INLET DAMPER POSITION SENSOR CIRCUIT
DTC B1434 MAX COOL DAMPER POSITION SENSOR CIRCUIT (DRIVER SIDE)
DTC B1435 MAX COOL DAMPER POSITION SENSOR CIRCUIT (PASSENGER SIDE)
DTC B1442 AIR INLET DAMPER CONTROL SERVOMOTOR CIRCUIT
DTC B1451 COMPRESSOR SOLENOID CIRCUIT
DTC B1461 EMISSION GAS NOX SENSOR CIRCUIT
DTCDescription
DTC B1244 LIGHT SENSOR CIRCUIT MALFUNCTION
DTC B1268 BACK-UP COMMUNICATION BUS MALFUNCTION
DTC B2402, B2403 TRANSISTOR RELAY OVERLOAD/OVERHEAT MALFUNCTION
DTC B2412, B2413 HEADLIGHT SWIVEL MOTOR LH/RH MALFUNCTION
DTC B2414 STEERING POSITION SENSOR MALFUNCTION
DTC B2415 VEHICLE SPEED SENSOR MALFUNCTION
DTC B2416 HEIGHT CONTROL SENSOR MALFUNCTION
DTC B2417, B2418 HEADLIGHT BEAM LEVEL CONTROL MOTOR LH/RH
MALFUNCTION

dynamic laser cruise control system.
Operation of the constant speed control mode is the same as that for the conventional type
cruise control system.
b. This system maintains the vehicle running at the speed that the driver has set, as long as there are
no vehicles ahead in the same lane. Then, the system maintains the vehicle distance that has been
set by the driver.
If the system detects a vehicle moving at a slower speed ahead while the driver is driving at a
constant speed, it closes the throttle valve to decelerate. If further deceleration is required, the
system controls the brake actuator in order to apply the brakes. Thereafter, if there are no vehicles
ahead within the set vehicle-to-vehicle distance because either the vehicle ahead or the driver has
changed lanes, the system accelerates slowly to reach the set vehicle speed and resumes driving at
the constant speed.
c. The constant speed control mode is designed to maintain a constant cruising speed. The vehicle-to-
vehicle distance control mode is designed to control cruising at a constant speed function,
deceleration cruising function, follow-up cruising function and acceleration cruising function.
d. The laser sensor and the distance control ECU (cruise control ECU) control the system while the
vehicle-to-vehicle distance control mode is in operation, and send signals to each actuator and
ECU.
e. In vehicle-to-vehicle distance control mode, the dynamic laser cruise control system receives
signals from the yaw rate & deceleration sensor and the steering angle sensor. Based on these
signals, it then estimates curve radius and compensates for information on the preceding vehicle
while turning. It can also compensate for the brake control when approaching another vehicle.
f. This system judges the existence of a vehicle in front and the distance to it based on the signals
from the laser sensor while the vehicle-to-vehicle distance control mode is in operation. Using this
information, the system informs the driver of any danger with the warning buzzer, performs brake
control, and turns on the stop lamp when approaching the vehicle in front.
g. The following illustration shows a control example under the following conditions: own vehicle
speed is 100 km/h (62 mph) and the speed of the vehicle in front is 80 km/h (50 mph).

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.

1.GENERAL
a. 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.
b. This system maintains the vehicle running at the speed that the driver has set, as long as there are
no vehicles ahead in the same lane. Then, the system maintains the vehicle distance that has been
set by the driver.
If the system detects a vehicle moving at a slower speed ahead while the driver is driving at a
constant speed, it closes the throttle valve to decelerate. If further deceleration is required, the
system controls the brake actuator in order to apply the brakes. Thereafter, if there are no vehicles
ahead within the set vehicle-to-vehicle distance because either the vehicle ahead or the driver has
changed lanes, the system accelerates slowly to reach the set vehicle speed and resumes driving at
the constant speed.
c. The constant speed control mode is designed to maintain a constant cruising speed. The vehicle-to-
vehicle distance control mode is designed to control cruising at a constant speed function,
deceleration cruising function, follow-up cruising function and acceleration cruising function.
d. The millimeter wave radar sensor and the distance control ECU (cruise control ECU) control the
system while the vehicle-to-vehicle distance control mode is in operation, and send signals to each
actuator and ECU.
e. In vehicle-to-vehicle distance control mode, the dynamic radar cruise control system receives
signals from the yaw rate & deceleration sensor and the steering angle sensor. Based on these
signals, it then estimates curve radius and compensates for information on the preceding vehicle
while turning. It can also compensate for the brake control when approaching another vehicle.
f. This system judges the existence of a vehicle in front and the distance to it based on the signals
from the radar sensor while the vehicle-to-vehicle distance control mode is in operation. Using this
information, the system informs the driver of any danger with the warning buzzer, performs brake
control, and turns on the stop lamp when approaching the vehicle in front.
g. The following illustration shows a control example under the following conditions: own vehicle
speed is 100 km/h (62 mph) and the speed of the vehicle in front is 80 km/h (50 mph).

Fig. 57: 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 system sounds the buzzer and the master warning light blinks to inform the driver.
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.
WIRING DIAGRAM
SEE WIRING DIAGRAM
.
INSPECTION PROCEDURE
SEE INSPECTION PROCEDURE
.
CIRCUIT DESCRIPTION
This DTC is output when the VSC system has a problem. Check the VSC system when this DTC is output.
Fig. 58: DTC P1578 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 an
y malfunctions in the communication

BUZZERS, RELAYS & TIMERS LOCATION
CIRCUIT PROTECTION DEVICES LOCATION
ComponentLocation
ABS CUT RelayOn engine room No. 3 R/B. See Fig. 7 .
ABS MTR RelayOn engine room No. 3 R/B. See Fig. 7 .
A/C COMP RelayOn engine room No. 1 R/B. See Fig. 5 .
AIR SUS RelayOn fusible link block. See Fig. 8 .
Clearance Sonar Buzzer (Front)Behind left side of dash. See Fig. 2 .
Clearance Sonar Buzzer (Rear)Near center of rear speaker shelf, at base of rear
window. See Fig. 19
.
C/OPN RelayOn engine room No. 1 R/B. See Fig. 5 .
D-ACC RelayOn driver side J/B. See Fig. 9 .
DEFOG RelayOn engine room No. 2 R/B. See Fig. 6 .
D-IG1 RelayOn driver side J/B. See Fig. 9 .
EFI MAIN RelayOn engine room No. 1 R/B. See Fig. 5 .
FAN RelayOn fusible link block. See Fig. 8 .
F/PMP RelayOn engine room No. 1 R/B. See Fig. 5 .
Headlight Cleaner Control RelayBelow left headlight. See Fig. 1 .
HEAD LP RelayOn engine room No. 1 R/B. See Fig. 5 .
IG1 RelayOn engine room No. 1 R/B. See Fig. 5 .
IG2 RelayOn engine room No. 1 R/B. See Fig. 5 .
Keyless BuzzerInside top of left front fender, near base of "A"
pillar. See Fig. 14
.
L-ACC RelayOn luggage room J/B. See Fig. 11 .
L-IG1 RelayOn luggage room J/B. See Fig. 11 .
P-ACC RelayOn driver side J/B. See Fig. 10 .
P-IG1 RelayOn driver side J/B. See Fig. 10 .
Rear Sunshade Control RelayBelow center of rear speaker shelf. See Fig. 4 .
RR S/SHADE RelayOn luggage room J/B. See Fig. 11 .
STARTER RelayOn fusible link block. See Fig. 8 .
Telephone Transceiver & Speaker RelayOn left side of luggage compartment. See Fig. 4 .
VSC Warning BuzzerBehind lower left side of dash. See Fig. 18 .
ComponentLocation

CONTROL UNITS LOCATION
Blower Motor ResistorCenter rear of vehicle. See Fig. 29 .
Engine Room No. 1 J/BOn left front of engine compartment, behind
headlight. See Fig. 1
.
Engine Room No. 1 R/BOn left front of engine compartment, behind
headlight. See Fig. 1
.
Engine Room No. 2 R/BOn left front of engine compartment, behind
headlight. See Fig. 1
.
Engine Room No. 3 R/BOn left rear of engine compartment. See Fig. 1 .
Fuel Pump ResistorLeft rear of engine compartment. See Fig. 13 .
Fusible Link BlockOn right rear of engine compartment. See Fig. 1 .
Luggage Room J/BOn left side of luggage compartment. See Fig. 4 .
Overhead J/BAt front of roof opening. See Fig. 4 .
ComponentLocation
AFS ECURight side of dash. See Fig. 2 .
Air Suspension ECUBehind right side of dash. See Fig. 2 .
Canister Pump ModuleLeft rear of vehicle. See Fig. 19 .
Clearance Sonar ECUOn left side of luggage compartment. See Fig. 4 .
Climate Control Seat ECU (Driver's Seat)Under right side of driver's seat. See Fig. 31 .
Climate Control Seat ECU (Front Passenger's Seat)Under front passenger's seat. See Fig. 31 .
Climate Control Seat ECU (Rear LH Seat)In left side of rear seat. See Fig. 32 .
Climate Control Seat ECU (Rear RH Seat)In right side of rear seat. See Fig. 32 .
Cooling Fan ECUOn front center of engine compartment, on radiator
support. See Fig. 1
.
Distance Control ECUBehind right side of dash. See Fig. 16 .
Door Lock Control ReceiverRight rear of luggage compartment. See Fig. 19 .
Driver Door ECUInside front of left front door. See Fig. 4 .
Driver Seat ECUBelow left side of driver's seat. See Fig. 31 .
Driver Side J/B ECUAt left kick panel. See Fig. 16 .
Engine Control ModuleOn left front of engine compartment, in protective
case. See Fig. 1
.
Front ControllerOn engine room No. 2 R/B. See Fig. 6 .
Front Passenger Door ECUInside right front door. See Fig. 4 .
Gateway ECUBehind left end of dash. See Fig. 16 .
Headlight Control ECU LHBehind left headlight. See Fig. 1 .
Headlight Control ECU RHBehind right headlight. See Fig. 1 .
Luggage Room J/B ECUOn left side of luggage compartment. See Fig. 4 .
Moon Roof Control ECUAt front of roof opening. See Fig. 4 .
On lower right side of luggage compartment. See

Fuel Lid Opener MotorOn left side of luggage compartment, behind left
rear fenderwell. See Fig. 19
.
Headlight Beam Level Control Actuator LHBehind left headlight. See Fig. 13 .
Headlight Beam Level Control Actuator RHBehind right headlight. See Fig. 13 .
Headlight Cleaner MotorBelow left headlight. See Fig. 13 .
Height Control CompressorOn right front of engine compartment. See Fig. 13 .
Luggage Compartment Door Closer MotorOn center rear of luggage compartment lid. See Fig.
28 .
Power Seat Module (Rear Passenger's RH Seat Slide
Control)Right side of rear seat. See Fig. 32 .
Power Seat Motor (Driver's Seat Cushion Control)Lower left side of driver's seat. See Fig. 31 .
Power Seat Motor (Driver's Seat Front Vertical
Control)Lower left side of driver's seat. See Fig. 31 .
Power Seat Motor (Driver's Seat Lifter Control)Lower right side of driver's seat bottom. See Fig.
31 .
Power Seat Motor (Driver's Seat Lumbar Support
Lower Side Control)Lower right side of driver's seat cushion. See Fig.
31 .
Power Seat Motor (Driver's Seat Lumbar Support
Upper Side Control)Upper right side of driver's seat back. See Fig. 31 .
Power Seat Motor (Driver's Seat Reclining Control)Lower left rear side of driver's seat bottom. See Fig.
31 .
Power Seat Motor (Driver's Seat Slide Control)In lower left side of driver's seat cushion. See Fig.
31 .
Power Seat Motor (Front Passenger's Seat Front
Vertical Control)In lower right side of front passenger's seat bottom.
See Fig. 31
.
Power Seat Motor (Front Passenger's Seat Head
Rest Control)In upper left side of front passenger's seat back. See
Fig. 31
.
Power Seat Motor (Front Passenger's Seat Lifter
Control)In lower left side of front passenger's seat bottom.
See Fig. 31
.
Power Seat Motor (Front Passenger's Seat Lumbar
Support Control)Lower left rear of front passenger seat cushion. See
Fig. 31
.
Power Seat Motor (Front Passenger's Seat Reclining
Control)Lower right side of front passenger's seat. See Fig.
31 .
Power Seat Motor (Front Passenger's Seat Slide
Control)Under passenger's seat cushion. See Fig. 31 .
Power Seat Motor (Rear Passenger's LH Seat Slide
Control)Left side of rear seat. See Fig. 32 .
Power Window Motor Front LHIn left front door. See Fig. 29 .
Power Window Motor Front RHIn right front door. See Fig. 29 .
Power Window Motor Rear LHIn left rear door. See Fig. 29 .
Power Window Motor Rear RHIn right rear door. See Fig. 29 .
Rear Blower MotorCenter rear of vehicle. See Fig. 29 .
Rear Damper Servo MotorRear center of luggage compartment. See Fig. 29 .