2003 LEXUS LS430 replacement

Fig. 142: Identifying Skid Control ECU Terminals
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OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)

AIR CONDITIONER TEST RESULT
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
A
2.INSPECT COOLER (ROOM TEMPERATURE SENSOR) THERMISTOR
a. Remove the cooler (room temperature sensor) thermistor.
b. Measure the resistance according to the value (s) in the table below.
Standard:
COOLER (ROOM TEMPERATURE SENSOR) THERMISTOR RESISTANCE
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C
Tester connectionConditionSpecified condition
A14-1 - A14-210°C (50°F)3.00 to 3.73 kohms
A14-1 - A14-215°C (59°F)2.45 to 2.88 kohms
A14-1 - A14-220°C (68°F)1.95 to 2.30 kohms
A14-1 - A14-225°C (77°F)1.60 to 1.80 kohms
A14-1 - A14-230°C (86°F)1.28 to 1.47 kohms
A14-1 - A14-235°C (95°F)1.00 to 1.22 kohms
A14-1 - A14-240°C (104°F)0.80 to 1.00 kohms
A14-1 - A14-245°C (113°F)0.65 to 0.85 kohms
A14-1 - A14-250°C (122°F)0.50 to 0.70 kohms
A14-1 - A14-255°C (131°F)0.44 to 0.60 kohms
A14-1 - A14-260°C (140°F)0.36 to 0.50 kohms

B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
Fig. 39: Inspecting Air Conditioning Amplifier (TR
- SG-2)
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A
4.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - COOLER
(ROOM TEMPERATURE SENSOR)THERMISTOR) (SEE ELECTRONIC CIRCUIT
INSPECTION PROCEDURE )
a. Measure the resistance according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER - COOLER (ROOM TEMPERATURE SENSOR)
THERMISTOR) RESISTANCE
OK (Checking from the PROBLEM SYMPTOMS TABLE)B
OK (Checking from the DTC)C

Temperature Sensor)Thermistor)
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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

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WIRING DIAGRAM

Result:
AIR CONDITIONER TEST RESULT
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT )
A
2.INSPECT ECM (TAM - E2)
Fig. 43: ECM Connector Wire Harness View

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a. Remove the ECM 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:
ECM (TAM - E2) VOLTAGE
HINT:
As the temperature increases, the voltage decreases.
Result:
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C
Tester connectionConditionSpecified condition
E3-18 (TAM) - E5-28 (E2)Ignition switch ON at 25°C (77°F)2.0 +/- 0.2V
E3-18 (TAM) - E5-28 (E2)Ignition switch ON at 40°C (104°F)1.4 +/- 0.2 V

ECM (TAM - E2) TEST RESULT
B: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
C: REPLACE ECM (SEE REPLACEMENT )
A: Go to next step
3.INSPECT A/C AMBIENT TEMPERATURE SENSOR
a. Remove the A/C ambient temperature sensor.
b. Measure the resistance according to the value (s) in the table below.
Fig. 44: Identifying Terminals Of A/C Ambient Temperature Sensor Connector

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NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C

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

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WIRING DIAGRAM
Fig. 48: Evaporator Temperature Sensor Circuit

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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
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