2004 MITSUBISHI ENDEAVOR traction control

The ECU incorporates the ABS-ECU, active skid control-ECU, and traction
control-ECU. The integral design allows joint operation of the TCL/ASC-ECU with
the ABS and coordinated control of the driving force and braking force. SYSTEM CONFIGURATION The Traction Control and Active Skid Control (TCL/ASC) System is a system that
adds a yaw rate sensor, a steering wheel sensor and master cylinder pressure sensor
(incorporated in hydraulic unit) to the ABS system. OVERVIEW OF CONTROL The TCL/ASC-ECU detects vehicle movement based on information from various
sensors and calculates a model of ideal vehicle movement. After comparing actual
and ideal movements, it acts to bring the actual vehicle movement closer to the
ideal model by controlling specific wheel brake force and governing engine output.
It restrains under-steering and over-steering through a corrective yaw moment, as
explained on the following pages. EXAMPLE OF ACTIVE SKID CONTROL OPERATION The Active Skid Control manages the vehicle attitude by creating a yaw moment
from altering the balance between the cornering force and each wheel's braking
mechanism.
For example, on a slippery surface, if the vehicle tends to be under-steered contrary
to the driver's intention, a yaw moment (a rotational moment) is created to restrain
the under-steering by increasing the rear-inside braking force. On the other hand,
when the vehicle tends to be over-steered, a yaw moment (a restorative moment) is
created to restrain the over-steering by increasing the front-outside braking force.
Furthermore, when it is determined that the vehicle is over-speeding, safe and stable
cornerin
g is enabled b
y deceleration from restrictin
g en
gine out
put.

2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor

Fig. 8: Identifying Example Of Active Skid Control Operation

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EXAMPLE OF THE EFFECT OF CONTROL
2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor

Fig. 9: Identifying Examples Of The Effect Of Control

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JOINT CONTROL The Active Skid Control transmits data necessary for control of the ABS and the
Traction Control, performing joint control.
2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor

Fig. 10: Identifying Joint Control Specification
s
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EXAMPLE OF OPERATION OF TRACTION CONTROL The Traction Control prevents drive force loss during slipping of the drive wheels
by automatically applying the brakes and sending engine torque reduction signal to
the PCM when the drive wheels slip or when driving on partly low-friction
surfaces. FAIL-SAFE AND DIAGNOSTIC FUNCTIONS The TCL/ASC-ECU regularly monitors input and out put signals. If an error is
detected in the system, the ECU sends a fail signal and the TCL/ASC indicator light
is illuminated or blinks. Various controls are processed depending on the cause of
malfunction as shown below. When the ABS system fails, the TCL/ASC system is
also suspended. However, when the TCL/ASC system fails, no other systems are
suspended. The appropriate indicator lights are illuminated/flashed.
The TCL/ASC-ECU includes the following functions to make system inspection
easier.
Diagnostic trouble code Display Data list Actuator test
All of the above operations can be carried out using scan tool MB991958.
ACTIVE SKID CONTROL SYSTEM OPERATION The TCL/ASC-ECU receives information from the PCM, the steering sensor, the G
and yaw-rate sensor and the wheel speed sensor. If the ECU determines that the
vehicle is tending to oversteer or understeer, it sends signals to the active skid
control system valves and the ABS solenoid valves to increase the fluid pressure to
the wheels.
The system closes the cut valve to shut the fluid channel to the suction valve, and
activates the
pum
p motor. The brake fluid, which is
pum
ped throu
gh the h
ydraulic

2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor

unit reservoir, will be supplied to the front left wheel during oversteering or the rear
right wheel during understeering when the vehicle is at right turn. Furthermore, the
system also controls the engine if the accelerator pedal is depressed excessively. DURING NORMAL BRAKING Fig. 11: During Normal Braking Diagram

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The brake fluid flows from the master cylinder to the cut valve and the inlet valve
to supply fluid pressure to the relevant wheels.

2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor

Fig. 12: Status Of Operation Valve Specification

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WHEN THE ABS FLUID PRESSURE IS DECREASING Fig. 13: ABS Fluid Pressure Is Decreasing Diagram

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The system closes the inlet solenoid valve to shut the fluid channel from the master
c
ylinder, and o
pens the outlet solenoid valve to return the brake fluid from the

2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor

wheel cylinders to the buffer chamber. This causes the wheel cylinder fluid pressure
to decrease. Then the system activates the pump motor to return the brake fluid
from the buffer chamber to the hydraulic unit reservoir.
Fig. 14: Status Of Operation Valve Specification

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WHEN THE ABS FLUID PRESSURE IS HOLDING Fig. 15: ABS Fluid Pressure Is Holding Diagram


2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor

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.
The system closes the inlet solenoid valve and the outlet solenoid valve to hold the
brake fluid pressure in the wheel cylinders.
Fig. 16: Status Of Operation Valve Specification

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WHEN THE ABS FLUID PRESSURE IS INCREASING
2004 Mitsubishi Endeavor LS
2004 BRAKES Traction Control, Active Skid Control System - Endeavor