2003 LEXUS LS430 air condition

Fig. 95: Identifying Height Control Compressor Motor Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK:Go to next step
5.CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL COMPRESSOR MOTOR - AIR
SUS RELAY) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Disconnect the AIR SUS relay from the fusible link block.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
Tester ConnectionSpecified Condition
1 (B) - 2 (for AIR SUS relay)Below 1 ohms
1 (B) - Body ground10 Kohms or higher

Fig. 97: Identifying Air Sus Relay Location
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK:Go to next step
6.CHECK HARNESS AND CONNECTOR (AIR SUS RELAY - BODY GROUND) (SEE
ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the voltage according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
Tester ConnectionSpecified Condition
4 (for AIR SUS relay) - Body ground10 to 14 V

Fig. 98: Identifying Air Sus Relay Location
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK:Go to next step
7.INSPECT HEIGHT CONTROL SOLENOID VALVE
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the ACTIVE TEST and operate it with the hand-held tester.
VEHICLE CONDITION / TEST DETAILS AIRSUS
ItemVehicle Condition / Test DetailsDiagnostic Note
FR SOLTurn OFF right front solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
FL SOLTurn OFF left front solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
RR SOLTurn OFF right rear solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
RL SOLTurn OFF left rear solenoid valve one second Operation of solenoid (clicking sound)

10.INSPECT FOR CLOGGED AIR TUBE
a. Check the air tube visually for a clog or damage (see ON
-VEHICLE INSPECTION ).
OK:
Air tube is not clogged or damaged.
NG: REPAIR OR REPLACE AIR TUBE
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The signal from the suspension control ECU operates the AIR SUS relay and the height control compressor
motor starts.
The height control compressor motor operates until the targeted vehicle height is reached. Then the height
control sensor sub-assy sends the signal to the suspension control ECU, and stops the height control compressor
motor.
Fig. 104: DTC C1751 And DTC C1752 Detecting Condition And Trouble Area

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.CHECK HEIGHT CONTROL COMPRESSOR CIRCUIT (SEE DTC C1742 HEIGHT
CONTROL COMPRESSOR CIRCUIT )
2.CHECK AIR LEAKAGE (SEE ON
-VEHICLE INSPECTION )
OK:
No leaks

NG: REPAIR OR REPLACE AIR TUBE
OK:Go to next step
3.INSPECT HEIGHT CONTROL SOLENOID VALVE
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position and turn the hand-held tester main switch on.
c. Select the item below in the ACTIVE TEST and operate it with the hand-held tester.
VEHICLE CONDITION / TEST DETAILS AIRSUS
d. Check the operation sound of the height control solenoid valve when the solenoid is turned on
through the ACTIVE TEST.
OK:
An operation sound is heard 1 second after the height control solenoid valve is turned on.
NG: Go to step 4
OK: Go to step 6
4.INSPECT HEIGHT CONTROL SOLENOID VALVE
HEIGHT CONTROL SOLENOID VALVE FRONT RH:
a. Disconnect the height control solenoid valve connector.
b. Connect terminal 3 (SLFR) to the battery positive (+) terminal, and terminal 2 (GND) to the battery
negative (-) terminal.
c. Check the operating sound of the height control solenoid valve.
OK:
It should make an operating sound (click).
ItemVehicle Condition / Test DetailsDiagnostic Note
FR SOLTurn OFF right front solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
FL SOLTurn OFF left front solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
RR SOLTurn OFF right rear solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard
RL SOLTurn OFF left rear solenoid valve one second
after turning it ONOperation of solenoid (clicking sound)
can be heard

POWER SOURCE CIRCUIT ).
NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE
OK:Go to next step
2.CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL SENSOR SUB-ASSY POWER
SOURCE) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Disconnect the height control sensor sub-assy connector.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT
RH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT
LH):
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (REAR RH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (REAR LH)
NG: CHECK HEIGHT CONTROL SENSOR SUB-ASSY CIRCUIT (SEE DTC C1711 RIGHT
FRONT HEIGHT CONTROL SENSOR CIRCUIT, DTC C1712 LEFT FRONT HEIGHT
CONTROL SENSOR CIRCUIT,DTC C1713 RIGHT REAR HEIGHT CONTROL SENSOR
CIRCUIT, DTC C1714 LEFT REAR HEIGHT CONTROL SENSOR CIRCUIT )
Fig. 110: Identifying Front Height Control Sensor Sub
-Assy Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Tester ConnectionSpecified Condition
H14-1 (SHB) - H14-4 (SHG)4.5 to 5.5 V
Tester ConnectionSpecified Condition
H13-1 (SHB) - H13-4 (SHG)4.5 to 5.5 V
Tester ConnectionSpecified Condition
H31-1 (SHB) - H31-3 (SHG)4.5 to 5.5 V
Tester ConnectionSpecified Condition
H30-1 (SHG) - H30-3 (SHB)4.5 to 5.5 V

Fig. 111: Identifying Rear Height Control Sensor Sub-Assy Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK:Go to next step
3.CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - BODY GROUND)
(SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Turn the ignition switch off.
b. Disconnect the suspension control ECU A21 connector.
c. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK:Go to next step
Tester ConnectionSpecified Condition
A21-23 (SBL3) - Body ground10 Kohms or higher

NORMAL CONDITION AIRSUS
d. Check the voltage
Standard:
10 to 14 V
NG: Go to step 5
OK:Go to next step
2.CHECK SOURCE VOLTAGE
a. Check the battery voltage.
Standard:
11 to 14 V
NG: REPLACE BATTERY
OK:Go to next step
3.INSPECT FUSE (AM1)
a. Remove the AM1 fuse from the driver side J/B.
b. Check fuse.
1. Check continuity of the AM1 fuse.
Standard:
Continuity
ItemNormal Condition
IG VOLTAGEActual ECU power supply voltage 10 to 14 V