Lexus ES300 (2002 year). Manual — part 113

CHASSIS – SUSPENSION AND AXLE

CH-39

211CH17

Absorber
Control
Switch

Stop Light Switch

DLC3

Front
Passenger
Acceleration
Sensor

Rear
Acceleration
Sensor

Skid Control
ECU

Steering
Angle Sensor

SW1

SW2

STP

TEM

TC

TS

SIL

SBL

SGFL
SGL

SBR
SGR

SGRR

HARD

FRO

SS2+

SS2-

Absorber
Control
ECU with
Driver
Acceleration
Sensor

TACH

FAL+
FAL–

FBL+
FBL-

FAR+
FAR-

FBR+
FBR-

RAL+
RAL-
RBL+
RBL-

RAR+
RAR-
RBR+
RBR-

Front Shock Absorber
and Actuator (LH)

Rear Shock Absorber
and Actuator (LH)

Front Shock Absorber
and Actuator (RH)

Rear Shock Absorber
and Actuator (RH)

ECM

4. Wiring Diagram

CHASSIS – SUSPENSION AND AXLE

CH-40

5. Function of Component

Component

Function

Steering Angle Sensor

Detects the steering direction and angle of the steering wheel.

Front Passenger
Acceleration Sensor

Detects the vehicle’s vertical (front passenger side) acceleration rate.

Rear Acceleration Sensor

Detects the vehicle’s vertical acceleration rate.

Speed Sensor (Front Right)

Detects the wheel speed of front right wheel.

Shock Absorber
and Actuator

Changes the damping force by the absorber control ECU signal.

Skid Control ECU

Converts the wheel speed signal from the speed sensors and sends it
to the absorber control ECU.

Crankshaft Position Sensor

Detects the engine speed.

ECM

Sends the engine speed signal from the crankshaft position sensor to
the absorber control ECU.

Absorber Control ECU with
Driver Acceleration Sensor

Determines the condition of the vehicle based on the signals

received from the sensors and switches and sends a control signal
to the actuator located in the shock absorber.

Uses an internal acceleration sensor to detect the vehicle’s vertical

(driver side) acceleration rate.

Stop Light Switch

Detects the brake condition.

Absorber Control Switch

Selects the damping force of the shock absorber.

CHASSIS – SUSPENSION AND AXLE

CH-41

211CH38

Absorber Control Switch Position

Absorber Control Switch

Damping
Force

HARD

SOFT

COMFORT

SPORT

211CH39

Front

Steering Angle Sensor

6. Construction and Operation of Component

Absorber Control Switch

As in the ’01 ES300, the absorber control switch uses a rotary type switch. By operating this switch, the
driver can select 4 types of damping forces of the shock absorbers.

Steering Angle Sensor

This sensor contain 3 photo interrupters with phases, and a slotted disc interrupts the light to turn the photo
transistor ON and OFF to detect the steering direction and angle.
This steering angle sensor is the same steering angle sensor as used for ABS with EBD & Brake Assist &
TRAC & VSC system.

CHASSIS – SUSPENSION AND AXLE

CH-42

211CH41

Front Passenger Acceleration Sensor

Rear Acceleration Sensor

211CH40

Sensor Tip

Acceleration Sensor Construction

Sensor Tip

Acceleration
Rate

R: Resistnace

R: +R

R: 0

R: – R

Acceleration Sensor

The driver acceleration sensor is built into the absorber control ECU.
The front passenger acceleration sensor is fitted to the instrument panel reinforcement.
The rear acceleration sensor is fitted to the right roof side inner.

These sensors are the piezoresistive type. When the vehicle accelerates, a piezoresistive sensor deflects,
thus changing its resistance. The resistance is then converted into an electrical signal in order to output a
voltage that is proportionate to the acceleration rate.