Lexus ES300 (2002 year). Service manual — part 112

CHASSIS – BRAKE

CH-74

VSC not

VSC Activated

Item

VSC not

Activated

Increase

Mode

Holding

Mode

Reduction

Mode

(1), (6)

Master Cylinder Cut
Solenoid Valve

OFF

(Open)

ON*

ON*

ON*

(1), (6)

Port: (A), (F)

(Open)

ON

ON

ON

(3), (4)

Reservoir Cut
Solenoid Valve

OFF

(Close)

ON

(Open)

ON

(Open)

ON

(Open)

(3), (4)

Port: (C), (D)

(Close)

(Open)

(Open)

(Open)

(2), (5)

Suction Solenoid
Valve

OFF

(Close)

OFF

(Close)

OFF

(Close)

OFF

(Close)

(2), (5)

Port: (B), (E)

(Close)

(Close)

(Close)

(Close)

(10)

Pressure Holding Valve
(Front Right)

OFF

(Open)

ON

(Close)

ON

(Close)

ON

(Close)

(10)

Port: (J)

(Open)

(Close)

(Close)

(Close)

(7)

Pressure Holding Valve
(Front Left)

OFF

(Open)

OFF

(Open)

ON

(Close)

ON

(Close)

(7)

Port: (G)

(Open)

(Open)

(Close)

(Close)

Front
Brake

(14)

Pressure Reduction Valve
(Front Right)

OFF

(Close)

OFF

(Close)

OFF

(Close)

OFF

(Close)

Brake

(14)

Port: (N)

(Close)

(Close)

(Close)

(Close)

(11)

Pressure Reduction Valve
(Front Left)

OFF

(Close)

OFF

(Close)

OFF

(Close)

ON

(Open)

(11)

Port: (K)

(Close)

(Close)

(Close)

(Open)

Wheel Cylinder Pressure

Right

—

—

—

—

Wheel Cylinder Pressure

Left

—

Increase

Hold

Reduction

(8)

Pressure Holding Valve
(Rear Right)

OFF

(Open)

ON

(Close)

ON

(Close)

ON

(Close)

(8)

Port: (H)

(Open)

(Close)

(Close)

(Close)

(9)

Pressure Holding Valve
(Rear Left)

OFF

(Open)

OFF

(Open)

ON

(Close)

ON

(Close)

(9)

Port: (I)

(Open)

(Open)

(Close)

(Close)

Rear
Brake

(12)

Pressure Reduction
Valve (Rear Right)

OFF

(Close)

OFF

(Close)

OFF

(Close)

OFF

(Close)

Brake

(12)

Port: (L)

(Close)

(Close)

(Close)

(Close)

(13)

Pressure Reduction
Valve (Rear Left)

OFF

(Close)

OFF

(Close)

OFF

(Close)

ON

(Open)

(13)

Port: (M)

(Close)

(Close)

(Close)

(Open)

Wheel Cylinder Pressure

Right

—

—

—

—

Wheel Cylinder Pressure

Left

—

Increase

Hold

Reduction

*: The solenoid valve controls the hydraulic pressure between “open” through “close” according to the

operating condition by adjusting continually.

CHASSIS – DRIVE SHAFT

CH-50

211CH51

Front Left-Hand

Front Right-Hand

Wheel Side

Rzeppa Type CVJ

Tripod Type CVJ

Differential Side

Differential Side

Tripod Type CVJ

Rzeppa Type CVJ

Wheel Side

211CH50

DRIVE SHAFT

DESCRIPTION

The drive shaft use the low-vibration tripod type CVJ (Constant-Velocity Joint) on the differential side, and
Rzeppa type CVJ on the wheel side.

CHASSIS – SUSPENSION AND AXLE

CH-37

211CH27

Front Shock
Absorber
and Actuator

Front Shock
Absorber
and Actuator

Front
Passenger
Acceleration
Sensor

Rear
Acceleration
Sensor

Stop Light
Switch

Steering Angle Sensor

Absorber Control
ECU with Driver
Acceleration Sensor

Absorber
Control
Switch

Rear Shock
Absorber
and Actuator

DLC3

Speed
Sensor
(Front RH)

Skid
Control
ECU

ECM

Crankshaft
Position
Sensor

Rear Shock
Absorber
and Actuator

ELECTRIC MODULATED SUSPENSION

1. General

Through electronic control, this system automatically controls the damping force of the shock absorbers, thus
realizes excellent riding comfort and controllability.

– Main Changes –

Construction and
Operation of
Component

2 acceleration sensors (front passenger and rear) have been provided.

The construction of the steering angle sensor has been changed.

The damping force of the shock absorbers has been changed.

System Control

The semi-active control of the damping force has been changed from

sky-hook control to non-linear H

∞

control in order to effect 4-wheel

independent control that constantly achieves an optimal damping force in
relation to the bumpiness of the road surface. As a result, excellent ride
comfort has been realized.

Imaginary roll damper control has been adopted for damping force control to

optimize the vehicle roll attitude during cornering. As a result, excellent
cornering stability and controllability have been realized.

Diagnosis

Outputs a 5-digit DTC (Diagnosis Trouble Code) and a 2-digit DTC to support

the M-OBD (Multiplex On-Board Diagnosis) system.

The DLC1 has been discontinued.

The method for erasing the DTCs has been changed.

–Reference–

To summarize, H

∞

control is a theory for designing a controller that meets the control specifications that

are represented by the H

∞

norm (a unit of measurement of the transfer function of the system). When this

is expanded into a non-linear system, it is called “non-linear H

∞

control”.

The “H” is the initial letter of the mathematician named Hardy (who studied the stability of control

systems) who advocated the mathematical space that is handled by this control theory. The “

∞

” represents

the “

∞

norm”, which is one of the mathematical units used for measuring the size of the signals.

2. System Diagram

CHASSIS – SUSPENSION AND AXLE

CH-38

211CH35

Stop Light Switch

Steering Angle Sensor

Front Passenger
Acceleration Sensor

Skid Control ECU

ECM

Absorber Control ECU with
Driver Acceleration Sensor

DLC3

Absorber Control Switch

Shock Absorber and Actuators

Rear Acceleration Sensor

Crankshaft
Position Sensor

Speed Sensor

Shock Absorber and Actuators

211CH36

3. Layout of Component