2003 LEXUS LS430 Suspension control

Acceleration value must change.
RESULT DESCRIPTION
B: Go to step 2
C: Go to step 3
D: REPLACE LEFT FRONT ACCELERATION SENSOR
HINT:
For the left front acceleration sensor failure, replace the suspension control ECU.
A: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
2.INSPECT HEIGHT CONTROL SENSOR SUB-ASSY FRONT RH
a. Remove the height control sensor sub-assy front RH.
b. Connect 3 dry batteries of 1.5 V in series.
c. Connect terminal 1 (SHB) to the batteries' positive (+) terminal, and terminal 4 (SHG) to the
batteries' negative (-) terminal, then apply voltage of approximately 4.5 V between terminals 4
(SHG) and 3 (SGFR) for the following conditions.
SENSOR CONDITION AND VOLTAGE SPECIFICATIONS
OKA
NG (right front acceleration sensor)B
NG (rear acceleration sensor)C
NG (left front acceleration sensor)D
Sensor conditionVoltage
Sensor stationaryApprox. 2.3 V
Sensor vibrating verticallyChange between approx. 1.0 to 4.0 V

HINT:
When the acceleration sensor is tilted, it may output the different value.
NG: REPLACE ACCELERATION SENSOR
OK:Go to next step
4.CHECK HARNESS AND CONNECTOR (ACCELERATION SENSOR - SUSPENSION
CONTROL ECU) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Disconnect the suspension control ECU A20 or A22 connector.
b. Measure the resistance according to the value (s) in the table below.
Fig. 51: Identifying Suspension Control ECU Connector Terminals

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
Fig. 53: Identifying Height Control Sensor Connector Terminals

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A22-15 (SBR3) - A32-3 (VGS)Below 1 ohms
A22-27 (SGRR) - A32-1 (GL1)Below 1 ohms
A22-12 (SGR3) - Body ground10 Kohms or higher
A22-15 (SBR3) - Body ground10 Kohms or higher
A22-27 (SGRR) - Body ground10 Kohms or higher

CIRCUIT DESCRIPTION
Absorber control actuator switches the damping force depending on the suspension control ECU signals.
Fig. 54: DTC C1725 And DTC C1728 Detecting Condition And Trouble Area

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WIRING DIAGRAM

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.
NORMAL CONDITION DESCRIPTION
d. Check the hardness of the absorber while operating the absorber control actuator level from 1 to 17
or from 17 to 1 through the ACTIVE TEST.
OK:
Hardness of the absorber becomes harder or softer.
NG: Go to step 2
OK: REPLACE SUSPENSION CONTROL ECU (SEE REPLACEMENT
)
2.INSPECT ABSORBER CONTROL ACTUATOR
a. Disconnect the absorber control actuator connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT RH)
ItemNormal Condition
DAMPER FR1 to 17 step (The absorber becomes softer as the level approaches to 1 and harder
as the level approaches to 17)
DAMPER FL1 to 17 step (The absorber becomes softer as the level approaches to 1 and harder
as the level approaches to 17)
DAMPER RR1 to 17 step (The absorber becomes softer as the level approaches to 1 and harder
as the level approaches to 17)
DAMPER RL1 to 17 step (The absorber becomes softer as the level approaches to 1 and harder
as the level approaches to 17)
Tester ConnectionSpecified Condition
1 (FBR+) - 3 (GND)12.0 to 12.8 ohms
2 (FAR+) - 3 (GND)12.0 to 12.8 ohms
3 (GND) - 4 (FBR-)12.0 to 12.8 ohms
3 (GND) - 5 (FAR-)12.0 to 12.8 ohms

Fig. 59: Identifying Absorber Control Actuator Rear LH Connector Terminals
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NG: REPLACE ABSORBER CONTROL ACTUATOR
OK:Go to next step
3.CHECK HARNESS AND CONNECTOR (ABSORBER CONTROL ACTUATOR - SUSPENSION
CONTROL ECU) (SEE ELECTRONIC CIRCUIT INSPECTION PROCEDURE
)
a. Disconnect the air suspension ECU A21 or A22 connector.
b. Measure the resistance according to the value (s) in the table below.
TESTER CONNECTION STANDARD SPECIFIED CONDITION STANDARD (FRONT RH)
Tester ConnectionSpecified Condition
A21-1 (FAR+) - S6-2 (FAR+)Below 1 ohms
A21-2 (FAR-) - S6-5 (FAR-)Below 1 ohms
A21-3 (FBR+) - S6-1 (FBR+)Below 1 ohms
A21-4 (FBR-) - S6-4 (FBR-)Below 1 ohms
A21-1 (FAR+) - Body ground10 Kohms or higher

Fig. 60: Identifying Suspension Control ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
A21-2 (FAR-) - Body ground10 Kohms or higher
A21-3 (FBR+) - Body ground10 Kohms or higher
A21-4 (FBR-) - Body ground10 Kohms or higher
S6-3 (GND) - Body groundBelow 1 ohms

Fig. 62: Identifying Suspension Control ECU Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.