Mazda Training manual - part 94

 

  Index      Mazda     Mazda Training Manual

 

Search            

 

 

 

 

 

 

 

 

 

Content   ..  92  93  94  95   ..

 

 

Mazda Training manual - part 94

 

 

Dynamic Driving Safety Systems 

TCS 

During TCS Control 

• 

When the wheel spin of the driven wheels exceed a specified limit, engine torque is 
reduced via the PCM by cutting the fuel off, changing the ignition timing, closing the 
throttle valve (only on vehicles with electronic throttle valve) and/or brake force is applied 
to the corresponding wheel in order to prevent it from spinning. 

• 

The traction control via the brake system can operate in three ways: 

– 

Pressure increase mode 

– 

Pressure hold mode 

– 

Pressure reduction mode 

• 

To simplify the explanation, the following pages describe TCS control when the right 
front wheel, on a front wheel drive vehicle, is spinning.  

 

Curriculum Training 

02-35 

TCS 

Dynamic Driving Safety Systems 

Pressure Increase Mode 

• 

Based on the input signals from the wheel speed sensors, the CM recognizes that the 
wheel is spinning. Based on all input signals, programmed parameters and internal 
calculations the CM decides whether it is necessary to actuate the brake system and/or 
to reduce the engine torque. The following steps explain how the wheel spin is prevented 
by activating the brake system. 

 
NOTE:  If the CM decides that the engine torque has to be reduced, it sends a corresponding 

signal to the PCM. The PCM then reduces the engine torque by cutting the fuel off, 
changing the ignition timing and/or by closing the throttle valve (only on vehicles with 
electronic throttle valve). 

 
• 

The CM actuates the traction switching solenoid valve in the brake circuit for the RF and 
LR wheel. This is done to separate the brake circuit from the brake master cylinder and 
to enable the pump to build up pressure in the corresponding brake circuit. 

• 

To make sure the TCS operation for the RF wheel does not affect the LR wheel, the CM 
activates the LR inlet solenoid valve. 

• 

The pump motor is switched on, pressure in the corresponding brake circuit is built up, 
and brake force is applied to the spinning wheel. 

 

LF-RR

OFF (open)

RF-LR

ON (closed)

LF

OFF (open)

RF

OFF (open)

LR

ON (closed)

RR

OFF (open)

LF

OFF (closed)

RF

OFF (closed)

LR

OFF (closed)

RR

OFF (closed)

Pump motor

ON (operating)

L2003_T02009

Traction control solenoid valve

Inlet solenoid valve

Outlet solenoid valve

 

 
 

02-36 Curriculum 

Training 

Dynamic Driving Safety Systems 

TCS 

 

 

L2003_02021 

 

Master cylinder 

Inlet solenoid valve 

ABS/TCS HU/CM 

Outlet solenoid valve 

Damper chamber 

Brake calliper LR 

Pump motor 

10 

Brake calliper RF 

Pump 

11 

Traction control solenoid valve RF/LR 

6 Reservoir 

  

 

Curriculum Training 

02-37 

TCS 

Dynamic Driving Safety Systems 

Pressure Hold Mode 

• 

When the CM detects that wheel spin is reduced, it switches to pressure hold mode by 
additionally activating (closing) the RF inlet solenoid valve, to maintain the built up 
pressure inside the corresponding brake calliper. Furthermore, the CM switches the 
pump motor off. 

 

LF-RR

OFF (open)

RF-LR

ON (closed)

LF

OFF (open)

RF

ON (closed)

LR

ON (closed)

RR

OFF (open)

LF

OFF (closed)

RF

OFF (closed)

LR

OFF (closed)

RR

OFF (closed)

Pump motor

OFF (stopped)

L2003_T02010

Traction control solenoid valve

Inlet solenoid valve

Outlet solenoid valve

 

 
 

02-38 Curriculum 

Training 

 

 

 

 

 

 

 

Content   ..  92  93  94  95   ..