2003 LEXUS LS430 Suspension control

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

1.DIAGNOSIS SYSTEM
a. Inspect the battery voltage.
Battery voltage: 11 to 14 V
If the voltage is below 11 V, recharge the battery before proceeding.
b. Check DLC3.
The suspension control ECU uses the CAN system and ISO 9141-2 for communication. The
terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.
Verify the conditions listed in the table below:
SGL2 (A22-23) -
GND (A20-4)GR - W-BHeight control sensor
ground (RL)AlwaysBelow 1
ohms
SBL2 (A22-24) -
GND (A20-4)BR - W-BHeight control sensor
power source (RL)IG switch ON4.5 to 5.5 V
SGR2 (A22-25) -
GND (A20-4)V - W-BHeight control sensor
ground (RR)AlwaysBelow 1
ohms
SBR2 (A22-26) -
GND (A20-4)B - W-BHeight control sensor
power source (RR)IG switch ON4.5 to 5.5 V
SGRR (A22-27) -
GND (A20-4)L - W-BAcceleration sensor
(rear)IG switch ON, keep the vehicle still
without any vertical movement for
1 secondApprox. 2.5
V
SHRR (A22-28) -
GND (A20-4)P - W-BHeight control sensor
(RR)IG switch ON0.5 to 4.5 V
SHRR (A22-28) -
GND (A20-4)P - W-BHeight control sensor
(RR)Engine idling, height control switch
"NORM"Approx. 2.5
V
SGFL (A22-29) -
GND (A20-4)B - W-BAcceleration sensor
(front)IG switch ON, keep the vehicle still
without any vertical movement for
1 secondApprox. 2.5
V
SHRL (A22-30) -
GND (A20-4)LG - W-BHeight control sensor
(RL)IG switch ON0.5 to 4.5 V
SHRL (A22-30) -
GND (A20-4)LG - W-BHeight control sensor
(RL)Engine idling, height control switch
"NORM"Approx. 2.5
V

HINT:
If the hand-held tester display shows UNABLE TO CONNECT TO VEHICLE when the cable of
the hand-held tester is connected to the DLC3, the ignition switch is turned to the ON position and
the tester is operated, there is a problem either on the vehicle side or tester side.
If communication is normal when the tester is connected to another vehicle, inspect the
DLC3 on the original vehicle.
If communication is still not possible when the tester is connected to another vehicle, the
problem is probably in the tester itself, so consult the Service Department listed in the tester's
instruction manual.
c. Indicator lamp
1. During the vehicle height control operation, the absorber control indicator lamp blinks when
there is any malfunction in the air suspension system.
CANL (14) - CG (4)LOW-level CAN bus
lineIG switch OFF3 Kohms or higher

Fig. 11: Identifying Absorber Control Indicator Lamp Location (1 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
d. DTCs (Normal mode)
1. DTCs are memorized in the suspension control ECU and read by using the hand-held tester
(SEE DTC CHECK/CLEAR
for the procedure of DTCs check).
e. Test mode
1. By switching from normal mode into test mode, you can inspect the height control switch,
absorber control switch, front acceleration sensor and rear acceleration sensor (SEE TEST
MODE PROCEDURE ).
2.CHECK INDICATOR LAMP
1. Turn the ignition switch to the ON position.
2. Check that the absorber control indicator lamp comes on for 2 seconds.
If the indicator check result is not normal, proceed to troubleshooting for the indicator lamp circuit.
TROUBLE AREA REFERENCE
Trouble AreaSee Procedure
Absorber control indicator lamp ABSORBER CONTROL INDICATOR LAMP

After repairing the malfunctions, clear the DTCs.
1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch to the ON position.
3. Erase the DTCs following the prompts on the tester screen.
Fig. 13: Connecting Hand
-Held Tester To DLC3
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
Refer to the hand-held tester operator's manual for further details.
1.FAIL-SAFE FUNCTION
a. When an air suspension system malfunction is detected under the normal control operation, the
suspension control ECU will suspend the switch control of the height control operation.
FAIL-SAFE CHART

a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Following the display on the hand-held tester, perform the "ACTIVE TEST".
VEHICLE CONDITION / TEST DETAILS
HINT:
If an abnormality is not found when the parts are inspected, inspect the suspension control ECU.
If a trouble code is displayed during the DTC check, check the circuit listed for that code.
DIAGNOSTIC TROUBLE CODE CHART
ItemVehicle Condition / Test DetailsDiagnostic Note
DAMPER FRChanges damper step (Front Right) / min.: 1
step, max.: 17 stepShock absorber hardens as
damper step increases
DAMPER FLChanges damper step (Front Left) / min.: 1
step, max.: 17 stepShock absorber hardens as
damper step increases
DAMPER RRChanges damper step (Rear Right) / min.: 1
step, max.: 17 stepShock absorber hardens as
damper step increases
DAMPER RLChanges damper step (Rear Left) / min.: 1 step,
max.: 17 stepShock absorber hardens as
damper step increases
FR UP &
DOWNRight front vehicle height / UP or DOWN-
FL UP & DOWNLeft front vehicle height / UP or DOWN-
RR UP &
DOWNRight rear vehicle height / UP or DOWN-
RL UP &
DOWNLeft rear vehicle height / UP or DOWN-
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
MOTOR
RELAYAIR SUS relay / ON or OFFOperation of solenoid (clicking
sound) can be heard
DTCDescription
DTC C1711, DTC C1712, DTC C1713,
DTC C1714, DTC C1714
RIGHT FRONT HEIGHT CONTROL SENSOR
CIRCUIT

Fig. 17: Diagnostic Trouble Code Information Chart (2 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
*1: For codes in the "Indicator Light" column with a "circ" mark, the absorber control indicator lamp blinks at 1
second intervals.
*2: For codes in the "Indicator Light" column with a " (xcirc)" mark, when trouble occurs, "HEIGHT HI" is
displayed on the multi-information display. Also, the master warning light is lit on the combination meter and
an alarm sounds.
*3: Since the relief pressure of the compressed air is 980 kPa (10 kgf/cm
2 , 142 psi), if vehicle height control is
attempted on a steeply sloping road, when the vehicle is overloaded, or when the vehicle height is jacked up
with the engine running, code "C1751" may be output and vehicle height control may be suspended. (This is not
abnormal.) In this case, however, when detecting the first error, approximately 10 minutes after the ignition
switch was turned to the ON position, vehicle height control is resumed. When the following errors are
detected, it takes 70 minutes until the control is resumed.
*4: If vehicle height control is operated while the wheels are removed or the vehicle is jacked up, code "C1752"
may be output, but this is not abnormal. When code "C1752" is output, vehicle height control is not carried out.
However, control is resumed if the ignition switch is turned off, then to the ON position again.
CIRCUIT DESCRIPTION
The height control sensor sub-assy controls the resistance value by following changes in vehicle height. The
suspension control ECU detects the change in vehicle height from the transformed voltage. The suspension
control ECU outputs a constant voltage of 5 V to the SHB terminal of the height control sensor sub-assy.
In the height control sensor, the voltage is changed due to resistance. The changed voltage is output from the

SHFR terminal of the height control sensor sub-assy to suspension control ECU, thus the vehicle height is
detected.
Fig. 18: Front Height Control Sensor Circuit Description

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
If DTC C1711, C1712, C1713 or C1714 is output, vehicle height control is suspended.
If the normal signal is output from the height control sensor sub-assy while suspending vehicle height
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48005500440057004c005200510003004c005600030044004f[so resumed when the ignition switch is
turned off once, then turned on again.