2003 LEXUS LS430 air conditioning

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
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
A: Go to next step
2.INSPECT AIR CONDITIONING AMPLIFIER (TE - SG)
a. Remove the A/C amplifier with connectors still connected.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER (TE - SG) VOLTAGE
HINT:
ItemMeasure Item/Display (Range)Normal ConditionDiagnostic
Note
EVAP
TEMPEvaporator temperature sensor / min.: -29.7°C (-
21.46°F) max.: 59.55°C (139.19°F)Actual evaporator
temperature is displayed-
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C
Tester connectionConditionSpecified condition
A36-20 (TE) - A36-15 (SG-7)Ignition switch ON at 0°C (32°F)2.0 to 2.4 V
A36-20 (TE) - A36-15 (SG-7)Ignition switch ON at 15°C (59°F)1.4 to 1.8 V

As the temperature increases, the voltage decreases.
Result:
AIR CONDITIONING AMPLIFIER (TE - SG) TEST RESULT
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
Fig. 49: Inspecting Air Conditioning Amplifier (TE
- SG)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
A: Go to next step
3.INSPECT A/C EVAPORATOR TEMPERATURE SENSOR
a. Remove the A/C evaporator temperature sensor.
b. Measure the resistance according to the value (s) in table below.
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C

HINT:
As the temperature increases, the resistance decrease (see the graph below).
Fig. 51: Resistance/Temperature Graph

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE A/C EVAPORATOR TEMPERATURE SENSOR
HINT:
When replacing the evaporator temperature sensor, the attached sub-harness should be replaced along
with the sensor.
OK: Go to next step
4.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - A/C
EVAPORATOR TEMPERATURE SENSOR) (SEE ELECTRONIC CIRCUIT INSPECTION
PROCEDURE )
a. Measure the resistance according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER - A/C EVAPORATOR TEMPERATURE SENSOR

RESISTANCE
Fig. 52: Checking Air Conditioning Amplifier Connector

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Tester connectionConditionSpecified condition
A36-20 (TE) - 1AlwaysBelow 1 ohms
A36-15 (SG-7) - 2AlwaysBelow 1 ohms
A36-20 (TE) - Body groundAlways10 kohms or higher
A36-15 (SG-7) - Body groundAlways10 kohms or higher

Fig. 53: Identifying Terminals Of A/C Evaporator Temperature Sensor Connector
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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. 54: DTC Detection Item Trouble Area Chart

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

B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
A: Go to next step
2.INSPECT AIR CONDITIONING AMPLIFIER (TFACEDr - SG-3)
a. Remove the A/C amplifier with connectors still connected.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER (TFACEDr - SG-3) VOLTAGE
HINT:
As the temperature increases, the volta
ge decreases.
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C
Tester connectionConditionSpecified condition
A13-15 (TFACEDr) - A13-10 (SG-3)Ignition switch ON at 25°C (77°F)1.8 to 2.2 V
A13-15 (TFACEDr) - A13-10 (SG-3)Ignition switch ON at 50°C (122°F)0.8 to 1.2 V

Fig. 56: Inspecting Air Conditioning Amplifier (TFACEDR - SG-3)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Result:
AIR CONDITIONING AMPLIFIER (TFACEDR - SG-3) TEST RESULT
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
A: Go to next step
3.INSPECT AIR DUCT SENSOR
a. Remove the air duct sensor.
b. Measure the resistance according to the value (s) in the table below.
Standard:
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C

AIR DUCT SENSOR RESISTANCE
HINT:
As the temperature increases, the resistance decreases.
Fig. 57: Inspecting Air Duct Sensor

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE AIR DUCT SENSOR
OK: Go to next step
4.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - AIR DUCT
SENSOR) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the resistance according to the value (s) in the table below.
Tester connectionConditionSpecified condition
D7-1 - D7-2at 0°C (32°F)14.5 to 19.0 kohms
D7-1 - D7-2at 25°C (77°F)4.8 to 5.2 kohms
D7-1 - D7-2at 50°C (122°F)1.6 to 2.0 kohms