2003 LEXUS LS430 Suspension Control actuator

Fig. 7: ABS & TRACTION Actuator - Traction Control
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Operation description
The skid control ECU detects vehicle's slip condition by receiving signals from the speed sensor
<004400510047000300280026003000030059004c004400030026002400310003004600520050005000580051004c004600440057004c00520051001100030037004b004800030056004e004c00470003004600520051005700550052004f00030028002600
380003004600520051005700550052004f0056000300480051[gine torque with the ECM,
vehicle position with suspension control ECU via CAN communication, and oil pressure with the
pump and solenoid valve. The SLIP indicator lamp blinks when the system is operating. TRAC
OFF switch stops traction control operation.
e. VSC (Vehicle Stability Control)
The VSC system helps prevent the vehicle from slipping sideways as a result of strong front wheel skid or
stron
g rear wheel skid during cornering.

Fig. 8: ABS & TRACTION Actuator - Vehicle Stability Control
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Operation description
The skid control ECU determines vehicle condition by receiving signals from the speed sensor, yaw rate
and deceleration sensor and steering angle sensor. The skid control ECU controls engine torque with the
ECM, vehicle position with suspension control ECU via CAN communication, and oil pressure with the
pump and solenoid valve. The warning light comes on and the buzzer sounds when the system is
operating.
2.ABS with EBD & BA & TRAC & VSC OPERATION
a. Skid control ECU calculates vehicle stability tendency based on the signal of sensors, speed sensor,
yaw rate and deceleration sensor and steering angle sensor. And it judges whether the control of
engine output torque by electronic control throttle and of wheel brake pressure by brake actuator
will operate or not by the calculation results.
b. The SLIP indicator blinks and the VSC buzzer sounds to inform the driver that the VSC system is
operating. The SLIP indicator also blinks when TRAC is operating, and the operation being
performed is displayed.
3.FAIL SAFE FUNCTION
a. When a failure occurs in the ABS with BA & TRAC & VSC systems, the ABS warning light and
the VSC warning light turns on and the ABS with BA & TRAC & VSC operations are prohibited.
In addition to this, when there is a failure that disables the EBD operation, the brake warning light
also comes on and the EBD operation is prohibited (see FAIL
-SAFE CHART ).
b. If some control is prohibited due to a malfunction during it's operation, that control will be cut off
gradually not to change stability of vehicle suddenly.
4.PRE-COLLISION BRAKE ASSIST SYSTEM (w/ PRE-COLLISION BRAKE ASSIST SYSTEM)

RC (A20-6) -
GND (A20-4)Y-R - W-BAIR SUS relay
Engine idling, height control switch
from "NORM" to "HIGH" during
compressor operation
8 V or more
CANH (A20-7) -
CANL (A20-8)BR - YCAN communication
lineIG switch OFF54 to 67
ohms
SW1 (A20-9) -
GND (A20-4)O - W-BAbsorber control switch
input signalEngine idling, absorber control
switch "NORM" position10 to 14 V
SW1 (A20-9) -
GND (A20-4)O - W-BAbsorber control switch
input signalEngine idling, absorber control
switch "SPORT" position0 to 1.5 V
SIL (A20-13) -
GND (A20-4)W-G - W-
BDiagnosis tester
communication lineIG switch ONPulse
generation
TD (A20-14) -
GND (A20-4)L-B - W-BHeight control is not
operatingIG switch ON10 to 14 V
HSW (A20-15) -
GND (A20-4)LG-B - W-
BHeight control switch
input signalIG switch ON, height control
switch "NORM" position10 to 14 V
HSW (A20-15) -
GND (A20-4)LG-B - W-
BHeight control switch
input signalIG switch ON, height control
switch "HIGH" position0 to 1.5 V
SLFR (A20-16) -
GND (A20-4)G-W - W-
BHeight control solenoid
valve (FR)IG switch ONBelow 1 V
SLFR (A20-16) -
GND (A20-4)G-W - W-
BHeight control solenoid
valve (FR)Engine idling, height control switch
from "NORM" to "HIGH" or
reverse
8 V or more
SLFL (A20-17) -
GND (A20-4)R-W - W-
BHeight control solenoid
valve (FL)IG switch ONBelow 1 V
SLFL (A20-17) -
GND (A20-4)R-W - W-
BHeight control solenoid
valve (FL)Engine idling, height control switch
from "NORM" to "HIGH" or
reverse
8 V or more
SBL1 (A20-18) -
GND (A20-4)LG-R - W-
BHeight control sensor
power source (FL)IG switch ON4.5 to 5.5 V
VH (A20-19) -
GND (A20-4)P - W-BHeight control indicator
output signalIG switch ON, height control
switch "HIGH"0 to 1.5 V
SBR1 (A20-20) -
GND (A20-4)V-R - W-BHeight control indicator
output signalIG switch ON, height control
switch "NORM"10 to 14 V
SBR1 (A20-20) -
GND (A20-4)V-R - W-BHeight control sensor
power source (FR)IG switch ON4.5 to 5.5 V
SGR1 (A20-21) -
GND (A20-4)R-L - W-BHeight control sensor
ground (FR)AlwaysBelow 1
ohms
SGL1 (A20-22) -
GND (A20-4)LG-B - W-
BHeight control sensor
ground (FL)AlwaysBelow 1
ohms
FAR+ (A21-1) -
FAR- (A21-2)O - R-YSuspension control
actuator (FR)IG switch ONBelow 1
ohms
FBR+ (A21-3) -
FBR- (A21-4)R-G - L-GSuspension control
actuator (FR)IG switch ONBelow 1
ohms
FAL+ (A21-5) -
FAL- (A21-14)G-B - G-RSuspension control
actuator (FL)IG switch ONBelow 1
ohms

FBL+ (A21-6) -
FBL- (A21-16)G-W - G-
OSuspension control
actuator (FL)IG switch ONBelow 1
ohms
SLRL (A21-7) -
GND (A20-4)P-L - W-BHeight control solenoid
valve (RL)IG switch ONBelow 1 V
SLRL (A21-7) -
GND (A20-4)P-L - W-BHeight control solenoid
valve (RL)Engine idling, height control switch
from "NORM" to "HIGH" or
reverse
8 V or more
SLRR (A21-8) -
GND (A20-4)P - W-BHeight control solenoid
valve (RR)IG switch ONBelow 1 V
SLRR (A21-8) -
GND (A20-4)P - W-BHeight control solenoid
valve (RR)Engine idling, height control switch
from "NORM" to "HIGH" or
reverse
8 V or more
RM+ (A21-17) -
GND (A20-4)BR-Y - W-
BMotor lock (+)
Engine idling, height control switch
from "NORM" to "HIGH" during
compressor operation
Below 1 V
RM- (A21-18) -
GND (A20-4)BR-B - W-
BMotor lock (-)AlwaysBelow 1
ohms
SHR2 (A21-19) -
GND (A20-4)W - W-BHeight control sensor
(HID rear)IG switch ON0.5 to 4.5 V
SHFR (A21-20) -
GND (A20-4)B-W - W-
BHeight control sensor
(FR)IG switch ON0.5 to 4.5 V
SHFR (A21-20) -
GND (A20-4)B-W - W-
BHeight control sensor
(FR)Engine idling, height control switch
"NORM"Approx. 2.5
V
SHF2 (A21-21) -
GND (A20-4)V-G - W-BHeight control sensor
(HID front)IG switch ON0.5 to 4.5 V
SHFL (A21-22) -
GND (A20-4)L - W-BHeight control sensor
(FL)IG switch ON0.5 to 4.5 V
SHFL (A21-22) -
GND (A20-4)L - W-BHeight control sensor
(FL)Engine idling, height control switch
"NORM"Approx. 2.5
V
SBL3 (A21-23) -
GND (A20-4)B - W-BHeight control sensor
power source (HID)IG switch ON4.5 to 5.5 V
SGL3 (A21-24) -
GND (A20-4)V-Y - W-BHeight control sensor
ground (HID)AlwaysBelow 1
ohms
RAR+ (A22-2) -
RAR- (A22-3)Y - SBSuspension control
actuator (RR)IG switch ONBelow 1
ohms
RBR+ (A22-4) -
RBR- (A22-5)LG - PSuspension control
actuator (RR)IG switch ONBelow 1
ohms
RAL+ (A22-6) -
RAL- (A22-7)L - GSuspension control
actuator (RL)IG switch ONBelow 1
ohms
RBL+ (A22-8) -
RBL- (A22-9)O - BRSuspension control
actuator (RLIG switch ONBelow 1
ohms
SGR3 (A22-12) -
GND (A20-4)W - W-BAcceleration sensor
ground (rear)AlwaysBelow 1
ohms
SBR3 (A22-15) -
GND (A20-4)R - W-BAcceleration sensor
power source (rear)IG switch ON4.5 to 5.5 V

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

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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. 67: Identifying Absorber Control Actuator Rear LH Connector 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 exhaust solenoid discharges high pressure air from the system by opening the solenoid valve according to
the si
gnal from the suspension control ECU.