2003 LEXUS LS430 air condition

Fig. 72: Identifying Exhaust Solenoid Valve Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK:Go to next step
4.CHECK HARNESS AND CONNECTOR (EXHAUST SOLENOID VALVE - BODY GROUND)
(SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
Tester ConnectionSpecified Condition

POWER SOURCE CIRCUIT ) is displayed, carry out the necessary inspection. If they are output at the
same time, carry out the necessary inspection for DTC C1774 first.
NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE
OK:Go to next step
2.PERFORM ACTIVE TEST BY HAND-HELD TESTER
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
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 3
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
3.INSPECT HEIGHT CONTROL SOLENOID VALVE
HEIGHT CONTROL SOLENOID VALVE FRONT:
a. Disconnect the height control solenoid valve connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (RH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (LH)
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
Tester ConnectionSpecified Condition
2 (GND) - 3 (SLFR)10 to 14 ohms

TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (REAR LH)
Fig. 81: Identifying Front Height Control Solenoid Valve Connector Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Tester ConnectionSpecified Condition
A21-8 (SLRR) - R18-1 (RH+)Below 1 ohms
A21-8 (SLRR) - Body ground10 Kohms or higher
Tester ConnectionSpecified Condition
A21-7 (SLRL) - R18-3 (LH+)Below 1 ohms
A21-7 (SLRL) - Body ground10 Kohms or higher

Fig. 85: DTC C1741 Detecting Condition And Trouble Area
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM
Fig. 86: Air Sus Relay Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.RECONFIRM DTC
a. Check DTCs (SEE DTC CHECK/CLEAR
).
1. Confirm if the DTC C1761 and/or C1774 is recorded.
OK:
DTC C1761 and/or C1774 is not output.
HINT:
If either DTC C1761 (ECU malfunction) (SEE DTC C1761 ECU MALFUNCTION
or DTC C1774

POWER SOURCE CIRCUIT ) is displayed, carry out the necessary inspection. If they are output at the
same time, carry out the necessary inspection for DTC C1774 first.
NG: REPAIR CIRCUIT INDICATED BY OUTPUT CODE
OK:Go to next step
2.PERFORM ACTIVE TEST BY HAND-HELD TESTER
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
d. Check the operation sound of the AIR SUS relay when operating it with the hand-held tester.
OK:
The operation sound of the AIR SUS relay can be heard.
NG: Go to step 3
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
3.INSPECT AIR SUS RELAY
a. Remove 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
NG: REPLACE AIR SUS RELAY
OK:Go to next step
Item
Vehicle Condition / Test
Details
Diagnostic Note
MOTOR RELAYAIR SUS relay / ON or OFFOperation of solenoid (clicking sound) can
be heard
Tester ConnectionSpecified Condition
1 - 210 Kohms higher
1 - 2Below 1 ohms (When battery voltage is applied to terminals 3 and 4)

Fig. 87: Inspecting Air Sus Relay
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
4.CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - AIR SUS RELAY)
(SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Disconnect the suspension control ECU A20 connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
Tester ConnectionSpecified Condition
A20-6 (RC) - 3 (for AIR SUS relay)Below 1 ohms
A20-6 (RC) - Body ground10 Kohms or higher

Fig. 89: Identifying Fusible Link Block Side 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 (AIR SUS RELAY - BODY GROUND) (SEE
ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
Tester ConnectionSpecified Condition
4 (for AIR SUS relay) - Body groundBelow 1 ohms

Fig. 93: Identifying Height Control Compressor Motor Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
3.CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT
CONTROL COMPRESSOR MOTOR) (SEE ELECTRONIC CIRCUIT INSPECTION
PROCEDURE )
a. Connect the height control compressor motor connector.
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
Tester ConnectionSpecified Condition
A21-17 (RM+) - A21-18 (RM-)6.4 to 7.4 ohms