2003 LEXUS LS430 air conditioning

Fig. 23: Identifying Rear Air Conditioning Amplifier Connector Front View
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
REAR AIR CONDITIONING AMPLIFIER CONNECTOR SPECIFICATIONS
Symbols
(Terminal No.)Wiring
colorTerminal
DescriptionConditionSpecification
RLO - GND
(A46-1 - A46-
6)
Y - W-BRear blower
switch signalIgnition switch ON. Rear A/C blower switch
manual OFF.Below 1.0 V
RLO - GND
(A46-1 - A46-
6)
Y - W-BRear blower
switch signalIgnition switch ON. Rear A/C blower switch
manual LO.10 to 14 V
RSLO - GND
(A46-2 - A46-
6)W-Y -
W-BRear A/C switch
signalIgnition switch ON. Rear A/C switch OFF.Below 1.0 V
RSLO - GND
(A46-2 - A46-
6)W-Y -
W-BRear A/C switch
signalIgnition switch ON. Rear A/C switch AUTO.10 to 14 V
R-B - GND
(A46-3 - A46-
6)L-W -
W-BPower source
(Back-up)Always10 to 14 V
SFRS - GND
(A46-4 - A46-
6)
V - W-B
Rear air inlet
control switch
signalIgnition switch ON. Front A/C blower motor
operates. Push "REC" switch.10 to 14 V
SFRS - GND
(A46-4 - A46-
6)
V - W-B
Rear air inlet
control switch
signalIgnition switch ON. Front A/C blower motor
operates. Push "FRS" switch. Ambient
temperature below -1 °C
Below 1.0 V
RMGV - GND
(A46-5 - A46-
6)G-Y -
W-BRear A/C switch
signalIgnition switch ON. Rear A/C switch OFF.10 to 14 V

1.STEP MOTORS INITIALIZING FUNCTION
STEP motor initializing procedure (Automatic initializing)
1. When the battery is reconnected and the ignition switch is turned to the ON position for the first
time, the initializing function of the STEP motors is activated. In this case, the "FRONT DEF"
indicator blinks.
SET TEMP SHIFT
(Set Temperature
Shift)
NORMALTo control with the shifted temperature
against the display temperature.+2C/+1C/ NORMAL -
1C / -2C
AIR INLET MODE
(Air Inlet Mode)AUTO
In case of turning the A/C ON when you
desire to make the compartment cool down
quickly, this is the function to change the
mode automatically to RECIRCULATED
mode.
MANUAL / AUTO
COMPRESSOR
MODE (Compressor
Mode)
AUTO
Function to turn the A/C ON automatically
by pressing the AUTO button when the
blower is ON and the A/C is OFF.
MANUAL / AUTO
COMPRS/DEF OPER
(Compressor/Air Inlet
DEF Operation)
LINK
Function to turn the A/C ON automatically
linking with the FRONT DEF button when
A/C is OFF.
NORMAL / LINK
MOTOR INITIALIZ
(STEP Motor
Initializing (IG/off))
OFFFunction to initialize the STEP motor after
the ignition switch is OFF.ON / OFF
EVAP CTRL
(External Variable
Control OFF)
AUTO
Function to set the evaporator control to the
AUTOMATIC position (AUTO) to save
power or to the coldest position
(MANUAL) to dehumidify the air and to
prevent the windows from fogging up.
MANUAL / AUTO
GAS SENS SHIFT
(Shift Emission Gas
Sensor Sensitivity)
NORMALFunction to change the sensitivity of the
exhaust gas sensor.
MU MORE /MORE / LI
MORE / NORMAL / LI
LESS / LESS / MU
LESS
AUTO MODE
(Cancel Auto Mode)AUTOFunction to swing the vent vans
automatically when A/C is ON.MANUAL / AUTO
BUTTON PRS BUS
(Cancel Operating
Switch Sound)
ONFunction to sound a buzzer when a button
is pressed.OFF / ON
FILTER SENS (Shift
Filter Clog Sensitivity)NORMALFunction to change the sensitivity of the air
conditioning filter choking sensor.LESS / NORMAL /
MORE
FOOT AIR LEAK
(Cancel Air Outlet
Foot II)
ONFunction to cut off the airstream felt
underfoot while the vehicle is moving.OFF / ON

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

Fig. 38: Resistance/Temperature Graph
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE COOLER (ROOM TEMPERATURE SENSOR) THERMISTOR
OK: Go to next step
3.INSPECT AIR CONDITIONING AMPLIFIER (TR - SG-2)
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 (TR - SG-2) VOLTAGE
HINT:
As the temperature increases, the voltage decreases.
Result:
AIR CONDITIONING AMPLIFIER TEST RESULT
Tester connectionConditionSpecified condition
A13-16 (TR) - A13-9 (SG-2)Ignition switch ON at 25°C (77°F)1.8 to 2.2 V
A13-16 (TR) - A13-9 (SG-2)Ignition switch ON at 40°C (104°F)1.2 to 1.6 V
NGA

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

Fig. 40: Checking Harness And Connector (Air Conditioning Amplifier - Cooler (Room

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

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

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