2003 LEXUS LS430 air conditioning

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 exhaust gas (NOx) outside the vehicle and sends a signal to the A/C amplifier.
Fig. 121: DTC Detection Item Trouble Area Chart

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

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 (NOX - SG-1)
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 (NOX - SG-1) VOLTAGE
HINT:
As the temperature increases, the voltage decreases.
Result:
AIR CONDITIONING AMPLIFIER (NOX - SG-1) TEST RESULT
NGA
OK (Checking from the PROBLEM SYMPTOM TABLE)B
OK (Checking from the DTC)C
Tester connectionConditionSpecified condition
A13-17 (NOX) - A13-8 (SG-1)Ignition switch ON at 10 to 35C° (50 to 95°F)1.0 to 4.5 V
NGA
OK (Checking from the PROBLEM SYMPTOMS TABLE)B
OK (Checking from the DTC)C

Fig. 123: Inspecting Air Conditioning Amplifier (NOX - SG-1)
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
3.INSPECT EXHAUST GAS SENSOR
a. Remove the exhaust gas sensor.
b. After keeping to apply battery voltage between terminals 3 and 6 for more than 120 seconds,
measure the resistance between terminals 1 and 2.
c. Measure the resistance according to the value (s) in the table below.
Standard:
EXHAUST GAS SENSOR RESISTANCE
Tester connectionConditionSpecified condition
E10-1 (S.G) - E10-4 (NOX)at 10 to 35°C (50 to 95°F)5 to 100 kohms

HINT:
<003a004b0048005100030057004b004800030056004800510056005200550003004c005600030048005b0053005200560048004700030057005200030057004b004800030048005b004b00440058005600570003004a00440056000f00030057004b004800
03005500480056004c0056005700440051004600480003004a[oes down.
Fig. 124: Inspecting Exhaust Gas Sensor

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE EXHAUST GAS SENSOR
OK: Go to next step
4.CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER - EXHAUST GAS
SENSOR) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the resistance according to the value (s) in the table below.
Standard:
AIR CONDITIONING AMPLIFIER - EXHAUST GAS SENSOR RESISTANCE

Fig. 125: Checking Harness And Connector (Air Conditioning Amplifier - Exhaust Gas Sensor)
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
The cool air bypass damper control servomotor is controlled by the A/C amplifier and moves the cool air bypass
damper to the desired position.
WIRING DIAGRAM
Fig. 126: Cool Air Bypass Damper Control Servomotor Circuit (Driver Side)

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

1.PERFORM ACTUATOR CHECK
a. Warm up the engine.
b. Set the actuator check mode (SEE ACTUATOR CHECK
).
c. Press the driver temperature up switch, and change to STEP operation.
d. Press the driver temperature up switch, and check the air flow by hand.
DISPLAY CODE - AIR FLOW POSITION
OK:
Cool air bypass damper changes in accordance with each display code.
NG: REPLACE AIR CONDITIONING AMPLIFIER (SEE REPLACEMENT
)
OK: Go to next step
2.INSPECT COOL AIR BYPASS SERVOMOTOR
a. Remove the cool air bypass servomotor.
b. Connect the positive (+) lead from the battery to terminal 4 and negative (-) lead to terminal 5, then
check that the lever turns to the "OPEN" position smoothly.
c. Connect the positive (+) lead from the battery to terminal 5 and negative (-) lead to terminal 4, then
check that the lever turns to the "SHUT" position smoothl
y.
Display codeAir flow position
0OPEN
1OPEN
2OPEN
3SHUT
4SHUT
5SHUT
6SHUT
7SHUT
8SHUT
9SHUT

Fig. 127: Inspecting Cool Air Bypass Servomotor
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPLACE COOL AIR BYPASS SERVOMOTOR
OK: Go to next step
3.CHECK HARNESS AND CONNECTOR (COOL AIR BYPASS SERVOMOTOR - AIR
CONDITIONING AMPLIFIER) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the resistance according to the value (s) in the table below.
Standard:
COOL AIR BYPASS SERVOMOTOR - AIR CONDITIONING AMPLIFIER RESISTANCE
Tester connectionConditionSpecified condition
A37-16 (ABODr) - C24-4 (MOPEN)AlwaysBelow 1 ohms
A37-17 (ABSDr) - C24-5 (MSNUT)AlwaysBelow 1 ohms
A36-11 (S5-5) - C24-1 (VZ)AlwaysBelow 1 ohms
A36-15 (SG-7) - C24-2 (GND)AlwaysBelow 1 ohms
C24-4 (MOPEN) - Body groundAlways10 kohms or higher
C24-5 (MSNUT) - Body groundAlways10 kohms or higher