LEXUS LS430 2003 Factory Repair Manual

Fig. 79: Identifying Height Control Solenoid Valve Rear LH Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK:
It should make an operating sound (click).
RESULT DESCRIPTION
HINT:
When a malfunction is found in the rear solenoid valve, replace the height control valve sub-assy No. 2.
B: REPLACE HEIGHT CONTROL VALVE SUB-ASSY NO. 1 (SEE REPLACEMENT
)
C: REPLACE HEIGHT CONTROL VALVE SUB-ASSY NO. 2 (SEE REPLACEMENT
)
A:Go to next step
4.CHECK HARNESS AND CONNECTOR (SUSPENSION CONTROL ECU - HEIGHT
OKA
NGC

CONTROL SOLENOID VALVE) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE)
a. Disconnect the suspension control ECU A20 or A21 connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT
RH)
Fig. 80: Identifying Suspension Control ECU Connector Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT
LH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (REAR RH)
Tester ConnectionSpecified Condition
A20-16 (SLFR) - F3-3 (RH+)Below 1 ohms
A20-16 (SLFR) - Body ground10 Kohms or higher
Tester ConnectionSpecified Condition
A20-17 (SLFL) - F3-1 (LH+)Below 1 ohms
A20-17 (SLFL) - Body ground10 Kohms or higher

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. 82: Identifying Rear Height Control Solenoid Valve Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK:Go to next step
5.CHECK HARNESS AND CONNECTOR (HEIGHT CONTROL 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 STANDARD (FRONT
RH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT
LH)
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (REAR RH)
Tester ConnectionSpecified Condition
F3-3 (RH+) - Body groundBelow 1 ohms
Tester ConnectionSpecified Condition
F3-1 (LH+) - Body groundBelow 1 ohms
Tester ConnectionSpecified Condition

TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (REAR LH)
Fig. 83: Identifying Front Height Control Solenoid Valve Connector Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
R18-1 (RH+) - Body groundBelow 1 ohms
Tester ConnectionSpecified Condition
R18-3 (LH+) - Body groundBelow 1 ohms

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390044004f0059004800030026005200510051004800460057[or Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The signal from the suspension control ECU switches the AIR SUS relay on, and then the height control
compressor motor starts.

Fig. 85: DTC C1741 Detecting Condition And Trouble Area
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WIRING DIAGRAM
Fig. 86: Air Sus Relay Wiring Diagram

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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
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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. 88: Identifying Suspension Control ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.