Tcs Control Outline; Features; Block Diagram; Tcs Control Operation - Mazda CX-9 2007 Service Highlights

DYNAMIC STABILITY CONTROL/ROLL STABILITY CONTROL

TCS CONTROL OUTLINE

• The traction control system (TCS) control actuates torque reduction through engine control, as well as using
brake control to control traction.
Note
• Engine control: Engine output is lowered by fuel cut and ignition timing control to reduce the traction,
preventing driving wheel slip.
• Brake control: Brake fluid pressure from the hydraulic unit (HU) to the driving wheel that is slipping is
increased, operating the brake and preventing driving wheel slip.

Features

• The left and right wheels are controlled at the same time by engine control. Therefore, when the road surface
friction coefficients differ between the left and right wheels, proper torque reduction cannot be performed
separately for each wheel. When this occurs, torque reduction is performed by independent left and right wheel
brake control, providing more stable vehicle control.
• The TCS OFF switch allows the driver to optionally enable/disable the TCS control at the driver's discretion.
— When both driving wheels are stuck, traction control according to the driver's operation can be performed
by inhibiting the TCS control.
— If the left and right driving wheel speeds are different when the TCS control is inhibited, brake control is
performed. Due to this, the ability to free the vehicle when one of the driving wheels is stuck has been
improved.
— To ensure constant vehicle stability, the TCS control returns to normal operation automatically when the
vehicle speed reaches the specification, even if the TCS control is inhibited by the TCS OFF switch.

Block Diagram

ABS WHEEL-SPEED
SENSOR (LF)
ABS WHEEL-SPEED
SENSOR (RF)
ABS WHEEL-SPEED
SENSOR (LR)
ABS WHEEL-SPEED
SENSOR (RR)
STEERING ANGLE
SENSOR
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TCS CONTROL OPERATION

• Traction control system (TCS) control detects a slipping drive wheel using the following signals, sends a torque
reduction request signal to the PCM and, at the same time, controls the solenoid valves and pump motor in the
dynamic stability control (DSC)/roll stability control (RSC) hydraulic unit (HU)/control module (CM).
— Vehicle wheel speed signals from the front and rear ABS wheel-speed sensors
— Engine torque signal from the PCM
— Steering angle signal from the body control module (BCM)
— Yaw rate, roll rate, forward-G and lateral-G signals from the combined sensor
— Fluid pressure signals from the brake fluid pressure sensors
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04-18–22
DSC/RSC HU/CM
CM HU
SOLENOID
VALVE
PUMP
MOTOR
CPU
BRAKE FLUID
PRESSURE
SENSOR
COMBINED
BCM
SENSOR
id041800818900
CALIPER PISTON
(LF)
CALIPER PISTON
(RF)
PCM
ac9uun00000519
id041800819000