2003 LEXUS LS430 diagram

Fig. 5: Air Conditioning System Diagram (1 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig. 6: Air Conditioning System Diagram (2 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.GENERAL
a. The air conditioning system has the following features:
In compliance with the temperature set at the temperature control switch, the neural network
control calculates the outlet temperature based on the input signals from various sensors. In
addition, corrections in accordance with the signals from the evaporative temperature sensor
and the water temperature sensor are added to control the outlet air temperature.
Controls the front and rear blower motors in accordance with the airflow volume that has
been calculated by the neural network control based on the input signals from various
sensors.
Automatically switches the outlets in accordance with the outlet mode ratio that has been
calculated by the neural network control based on the input signals from various sensors.
Automatically controls the air inlet control damper in accordance with the airflow volume
that has been calculated by the neural network control.
Turns the compressor on/off and controls the discharge capacity based on the signals from
various sensors.
Based on the signals from the ambient temperature sensor, this control calculates the outside
temperature, which is then corrected in the air conditioner ECU, and shown in the multi-
information display in the combination meter.
Switched the rear defogger and outside rear view mirror heaters on for 15 minutes when the
rear defogger switch is switched on. Switched them off if the switch is pressed while they are
operating.
Controls the orientation and the angle of the front center register based on the input signals
from various sensors and on the outlet mode.
Determines whether the clean air filter (for the front A/C) is clogged by monitoring the air
inlets, and airflow volume.
The A/C amplifier automatically controls the air inlets based on the signals from the smog
ventilation sensor.
Improves the air quality by linking the air inlet control damper and the blower motor (for the
rear A/C and air purifier), based on the signals from the exhaust gas sensor and the smoke
sensor.
Checks the sensors in accordance with operation of the air conditioner switches.
2.MODEL POSITION AND DAMPER OPERATION

By operating each of the A/C control switches as shown in the diagram below, it is possible to enter the
diagnostic check mode.
Fig. 11: Operation Methods Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
2.CHECK DLC3
a. The vehicle's ECM uses CAN and the to ISO 9141-2 for communication protocol. The terminal
arrangement of the DLC3 complies with SAE J1962 and meets the ISO 9141-2 format.

Fig. 34: Diagnostic Trouble Code Information Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
*1 If the room temperature is approximately -20°C (-4°F) or lower, DTC B1411/11 may be output even
though the system is normal.
*2 If the ambient temperature is approximately -50°C (-58°F) or lower, a DTC may be output even
though the system is normal.
*3 If the check is being performed in a dark place, DTC B1421/21 (solar sensor circuit abnormal) could
be displayed. In this case, perform DTC check again while shining a light, such as inspection light, on the
solar sensor. If DTC B1421/21 is still displayed, there could be trouble in the solar sensor circuit.
*4 If the check is being performed in a dark place, DTC B1424/24 (solar sensor circuit abnormal) could
be displayed. In this case, perform DTC check again while shining a light, such as inspection light, on the
solar sensor. If DTC B1424/24 is still displayed, there could be trouble in the solar sensor circuit.
*5 If the check is being performed in a dark place, DTC B1421/21 (solar sensor circuit abnormal) could
be displayed. In this case, perform DTC check again while shining a light, such as inspection light, on the
solar sensor. If DTC B1421/21 is still displayed, there could be trouble in the solar sensor circuit.
CIRCUIT DESCRIPTION
This sensor detects the interior temperature that is used as the basis for temperature control and sends
appropriate signals to the A/C amplifier.
Fig. 35: DTC Detection Item Trouble Area Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM

Temperature Sensor)Thermistor)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The sensor connected to the ECM detects fluctuations in the ambient temperature that is used for controlling the
interior temperature. The sensor sends a signal to the A/C amplifier via the ECM.
Fig. 41: DTC Detection Item Trouble Area Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM

OK: REPLACE ECM (SEE REPLACEMENT)
CIRCUIT DESCRIPTION
This sensor detects the evaporator temperature and sends the appropriate signals to the A/C amplifier. It is used
for frost prevention, temperature and time-lag air flow control.
Fig. 47: DTC Detection Item Trouble Area Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM
Fig. 48: Evaporator Temperature Sensor Circuit

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE

WIRING DIAGRAM
Fig. 55: Air Duct Sensor Circuit (Driver Side)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.READ VALUE ON HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and push the hand-held tester main switch on.
c. Select the item below in the DATA LIST, and read the display on the hand-held tester.
DATA LIST / AIR CONDITIONER:
DATA LIST / AIR CONDITIONER
OK:
The display is as specified in the normal condition.
Result:
AIR CONDITIONER TEST RESULT
ItemMeasure Item/Display (Range)Normal ConditionDiagnostic
Note
DUCT
TEMP-DDuct sensor (Driver side) / min.: -12.7°C
(9.14°F) max.: 76.55°C (169.79°F)Actual duct temperature is
displayed (Driver side)-

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
CIRCUIT DESCRIPTION
This sensor detects the register temperature and sends the appropriate signals to the A/C amplifier.
Fig. 59: DTC Detection Item Trouble Area Chart

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WIRING DIAGRAM
Fig. 60: Air Duct Sensor Circuit (Passenger Side)

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.READ VALUE ON HAND-HELD TESTER