2003 LEXUS LS430 Identifying ac

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

Fig. 53: Identifying Terminals Of A/C Evaporator Temperature Sensor Connector
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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

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Fig. 147: Identifying Location Of Fuse (A/C)
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OK: Go to next step
3.INSPECT AIR CONDITIONING AMPLIFIER (B - BODY GROUND)
a. Remove the A/C amplifier assy and disconnect the connector.
b. Measure the voltage according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER (B - BODY GROUND) VOLTAGE
NG: REPAIR OR REPLACE WIRE HARNESS (AIR CONDITIONING AMPLIFIER -
BATTERY)
Tester connectionConditionSpecified condition
A11-21 (+B) - Body groundAlways10 to 14 V

Fig. 155: Identifying Location Of Fuse (P-ACC)
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OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (AIR CONDITIONING
AMPLIFIER - BATTERY)
CIRCUIT DESCRIPTION
The blower motor is operated by signals from the A/C amplifier assy. Blower motor speed signals are
transmitted by changes in the duty ratio.
Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity
in one cycle, B is the period of non-continuity.
The blower motor controller controls the blower motor speed.

Fig. 156: Identifying Blower Motor Circuit Description
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WIRING DIAGRAM
Fig. 157: Blower Motor 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 displa
y on the hand-held tester.

Fig. 158: Identifying Location Of Fuse (Heater)
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OK: Go to next step
5.CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - AIR CONDITIONING
AMPLIFIER) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the resistance according to the value (s) in the table below.
Standard:
BLOWER MOTOR - AIR CONDITIONING AMPLIFIER RESISTANCE
Tester connectionConditionSpecified condition
A11-5 (BLW) -B2-2 (SI)AlwaysBelow 1 ohms
A11-5 (BLW) - Body groundAlways10 kohms or higher

Fig. 164: Identifying Waveform Between Terminal BLW (A11-5) Of A/C Amplifier And Body
Ground
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OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
CIRCUIT DESCRIPTION
This is the backup power source for the rear A/C amplifier. Power is supplied even when the ignition switch is
off and is used for memory, etc.
WIRING DIAGRAM

Fig. 166: Identifying Location Of Fuse (RR ECU-B)
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NG: CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO
FAILURE FUSE (RR ECU-B)
OK: Go to next step
2.INSPECT REAR AIR CONDITIONING AMPLIFIER (R-B - BODY GROUND)
a. Remove the rear A/C amplifier assy and disconnect the connector.
b. Measure the voltage according to the value (s) in the table below.
Standard:
REAR AIR CONDITIONING AMPLIFIER (R-B - BODY GROUND) VOLTAGE
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (REAR AIR CONDITIONING
AMPLIFIER -BATTERY)
Tester connectionConditionSpecified condition
A46-3 (R-B) - Body groundAlways10 to 14 V