LEXUS LS430 2003 Factory Repair Manual

Fig. 107: Identifying Height Control Solenoid Valve Rear RH Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
RESULT DESCRIPTION
HINT:
When a malfunction is found in the rear solenoid valve, replace the height control valve sub-assy No. 2.
HEIGHT CONTROL SOLENOID VALVE REAR LH:
a. Disconnect the height control solenoid valve connector.
b. Connect terminal 3 (SLRL) 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).
OKA
NGC

Fig. 108: Identifying Height Control Solenoid Valve Rear LH Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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
5.INSPECT EXHAUST SOLENOID VALVE
a. Disconnect the exhaust solenoid valve connector.
b. Connect terminal 3 (SLEX) to the battery positive (+) terminal, and terminal 2 (GND) to the battery
ne
gative (-) terminal.
OKA
NGC

c. Check the operating sound of the exhaust solenoid valve.
OK:
It should make an operating sound (click).
HINT:
When a malfunction is found in the exhaust solenoid valve, replace the height control compressor assy.
NG: REPLACE HEIGHT CONTROL COMPRESSOR ASSY (SEE REPLACEMENT
)
OK:Go to next step
6.INSPECT HEIGHT CONTROL SENSOR LINK SUB-ASSY
a. Inspect and adjust the height control sensor link sub-assy (see ON
-VEHICLE INSPECTION ).
NG: REPLACE HEIGHT CONTROL SENSOR LINK SUB-ASSY
OK: CHECK AND REPAIR OR REPLACE PARTS
Air tube is clogged (see ON-VEHICLE INSPECTION ).
Compressor is faulty (see REPLACEMENT ).
Height control sensor sub-assy is faulty (see REPLACEMENT - HEIGHT CONTROL
SENSOR SUB-ASSY FRONT , REPLACEMENT - HEIGHT CONTROL SENSOR SUB-
ASSY REAR LH ).
Foreign material in the height control solenoid valve and/or exhaust solenoid valve (see
REPLACEMENT
- HEIGHT CONTROL COMPRESSOR ASSY , REPLACEMENT -
HEIGHT CONTROL VALVE SUB
-ASSY NO.1 , REPLACEMENT - HEIGHT CONTROL
VALVE SUB-ASSY NO.2 ).
Suspension control ECU malfunction (see REPLACEMENT ).
CIRCUIT DESCRIPTION

Fig. 109: DTC C1761 Detecting Condition And Trouble Area
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.CONFIRM DTC
a. Check DTCs (SEE DTC CHECK/CLEAR
).
1. Confirm if DTC C1774 is recorded.
OK:
DTC C1774 is not output.
HINT:
If DTC C1774 (power source circuit) is displa
yed, carry out the inspection necessary (SEE DTC C1774

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

Fig. 112: Identifying Suspension Control ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
4.INSPECT SUSPENSION CONTROL ECU (ECU POWER SOURCE)
a. Turn the ignition switch off.
b. Measure the voltage according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION
Tester ConnectionSpecified Condition
A20-1 (B) - A20-4 (GND)10 to 14 V

Fig. 113: Identifying Suspension Control ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: CHECK POWER SOURCE CIRCUIT (SEE DTC C1774 POWER SOURCE CIRCUIT
)
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
When the ignition switch is turned to the ON position, the D-IG1 relay is activated and battery voltage is
applied to terminal B of the suspension control ECU. When the ignition switch is turned off, the D-IG1 relay is
de-energized and the power source is cut off.
This power source energizes the suspension control actuator, height control solenoid valve, D-IG1 relay, each
IC and sensor.

Fig. 114: DTC C1774 Detecting Condition And Trouble Area
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM
Fig. 115: Power Source Wiring Diagram

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT SUSPENSION CONTROL ECU
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 DATA LIST and read its value displa
yed on the hand-held tester.

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