Lexus ES300 (2002 year). Manual — part 115

CHASSIS – SUSPENSION AND AXLE

CH-47

211CH46

Steering Angle
Sensor

Acceleration Sensors

Shock
Absorber
Stroke
Information

Imaginary
Roll Damper
Control

Absorber Control ECU

211CH55

’02 ES300

’01 ES300

Center of Gravity

Center of Grabity

211CH54

Imaginary Roll Damper Control

To effect this control, the stroke information of the shock absorbers is calculated based on the information

from the 3 acceleration sensors and a steering angle sensor. Thus, the driving conditions of the vehicle are
detected.

Changes the damping force to control the vehicle posture during cornering. As a result, excellent stability

and controllability have been realized during cornering. This control assumes that two types of shock
absorbers, (one for restraining roll and the other for restraining lift) are provided at an imaginary point on
the inside of the turn of the vehicle. The function of these shock absorbers is to prevent the center of gravity
of the vehicle from rising.
The damping force of the front and rear shock absorbers is controlled in order to control the vehicle’s
posture as in this imaginary condition.

CHASSIS – SUSPENSION AND AXLE

CH-48

Diagnosis

When the absorber control ECU detected a malfunction, the absorber control ECU makes a DTC (Diagnosis
Trouble Code) of that malfunction is stored in memory.

– Changes –

The method for erasing the DTCs has been changed as follows (the DTCs on the ’01 ES300 were erased

by turning the ignition switch OFF):
Using the SST (09843-18040), short terminals Tc and CG of DLC3. Turn the ignition switch ON, and
press the brake pedal 8 or more times within approximately 5 seconds.

The DTCs can also be erased through the use of a hand-held tester.
The DLC1 has been discontinued.
M-OBD (Multiplex On-Board Diagnosis) system has been adopted. This system can output 5-digit DTC

to the hand-held tester, which are more detailed than the previous 2-digit DTC.

DTC Chart

DTC No.

Detection Item

DTC No.

Detection Item

C1715 / 15

Front driver acceleration sensor
malfunction

C1777 / 77

Steering angle sensor signal
malfunction

C1716 / 16

Front passenger acceleration
sensor malfunction

C1779 / 79

Engine speed signal malfunction

C1717 / 17

Rear acceleration sensor
malfunction

C1782 / 82

Stop light switch signal does not
input

C1725 / 21

Short / open circuit in front right
absorber control actuator circuit

C1787 / 87

Absorber control switch signal
malfunction

C1726 / 22

Short / open circuit in front left
absorber control actuator circuit

C1791 / 91

Front driver acceleration sensor
malfunction

C1727 / 23

Short / open circuit in rear right
absorber control actuator circuit

C1792 / 92

Front passenger acceleration
sensor malfunction

C1728 / 24

Short / open circuit in rear left
absorber control actuator circuit

C1793 / 93

Rear acceleration sensor
malfunction

C1774 / 74

Low battery positive voltage or
abnormally high positive voltage

C1794 / 94

Front right speed sensor
malfunction

C1776 / 76

Vehicle speed sensor signal
malfunction

C1797 / 97

Engine speed signal malfunction

Refer to the 2002 LEXUS ES300 Repair Manual (Pub. No. RM 911U).

CHASSIS – SUSPENSION AND AXLE

CH-49

208CH19

Double-Row Angular
Ball Bearing

Lock Nut (12-point)

208CH20

Double-Row Angular
Ball Bearing

AXLE

1. Front Axle

The front axle use a double-row angular ball bearing which offers low rolling resistance.
A lock nut (12-point) has been adopted and staked for tightening the axle hub in order to ensure the

tightening performance.
This nut cannot reused.

A lead-free material is used in the front axle hub to address environmental concerns.

2. Rear Axle

The rear axle use a double-row angular ball bearing which offers low rolling resistance.
Part of the inner race is integrated with the shaft, thus optimizes the high rigidity.

CHASSIS – BRAKE

CH-75

151CH31

Level of Strolng
Under Steering
or Over Steering

Start to throlttle Control

Start to Brake Control

Brake Control Completed

Throttle Control Completed

Amount of
Cehicle
Condition

Open

High

Time

Engine Torque

Brake Wheel
Cylinder Fluid
Pressure*

9. Skid Control ECU

VSC

Based on the 4 type of sensor signals received from the speed sensors, yaw rate sensor, deceleration sensor
and steering sensor, the skid control ECU calculates the amount of vehicle condition.
If a strong understeer or oversteer tendency is created during an emergency avoidance maneuver or
cornering, and the skid control ECU determines that the amount of vehicle condition exceeds a prescribed
value, it controls the engine torque through throttle and the brake fluid pressure according to the amount
of the vehicle condition.

*: The wheel cylinder that activates varies depending on the condition of the vehicle.

Initial Check

After the ignition is turned ON, and the vehicle attains an approximate speed of 6 km / h (4 mph) or more
only at first time, the skid control ECU performs the initial check.
The functions of each solenoid valve and pump motor in the brake actuator are checked in order.