Subaru Legacy/Outback

1999-2003 of release

Repair and car operation

System of dynamic stabilisation (VDC) - the general information, a functioning principle

The scheme of an arrangement of components VDC and adjacent systems


1 — Hydromodulator VDC 2 — the pressure Valve-terminator 3 — the engine management Module (ECM) 4 — the Main brake cylinder (ГТЦ) 5 — the Diagnostic socket 6 — Control lamp ABS 7 — Control lamp VDC 8 — the Alarm indicator of activation VDC 9 — the Alarm indicator of switching-off VDC 10 — the Gauge of an angle of rotation of a steering wheel	11 — Socket DLC for connection SSM 12 — Wheel gauges ABS 13 — Rotors of wheel gauges 14 — Wheel cylinders 15 — the Gauge of cross-section overloads (G) and intensity of withdrawal 16 — TCM 17 — the Module of management VDC 18 — the pressure Gauge 19 — the Switch of deactivation VDC

Principle of functioning VDC at drift on turn


1 — Forces of reaction of braking	2 — the Withdrawing moment

Principle of functioning VDC at insufficient reaction of the car to wheel turn


1 — Forces of reaction of braking	2 — the Withdrawing moment

Hydromodulator VDC functioning in a mode of normal braking (on an example of a contour of one wheel)


1 — Tank GTTS 2 — ГТЦ 3 — the pressure Gauge 4 — the Port is opened 5 — the Port is closed 6 — the Soaking up electromagnetic valve 7 — Otsechnoj the electromagnetic valve 8 — the Control valve 9 — Deaktivirovan 10 — Deaktivirovan 11 — Dempfernaja the chamber 12 — the Port is opened	13 — the Inlet electromagnetic valve 14 — the Pump 15 — the Control valve 16 — Deaktivirovan 17 — the Electromotor 18 — the Wheel cylinder 19 — the Final electromagnetic valve 20 — the Port is closed 21 — Deaktivirovan 22 — the Tank

Hydromodulator VDC functioning in a mode of dump of pressure at the squeezed out pedal of a foot brake (on an example of a contour of one wheel)


1 — Tank GTTS 2 — ГТЦ 3 — the pressure Gauge 4 — the Port is opened 5 — the Port is closed 6 — the Soaking up electromagnetic valve 7 — Otsechnoj the electromagician-nitnyj the valve 8 — the Control valve 9 — Deaktivirovan 10 — Deaktivirovan 11 — Dempfernaja the chamber	12 — the Port is closed 13 — the Inlet electromagnetic valve 14 — the Pump 15 — the Control valve 16 — It is activated 17 — the Electromotor 18 — the Wheel cylinder 19 — the Final electromagnetic valve 20 — the Port is opened 21 — It is activated 22 — the Tank

Hydromodulator VDC functioning in a mode of deduction of pressure at the squeezed out pedal of a foot brake (on an example of a contour of one wheel)


1 — Tank GTTS 2 — ГТЦ 3 — the pressure Gauge 4 — the Port is opened 5 — the Port is closed 6 — the Soaking up electromagnetic valve 7 — Otsechnoj the electromagnetic valve 8 — the Control valve 9 — Deaktivirovan 10 — Deaktivirovan 11 — Dempfernaja the chamber	12 — the Port is closed 13 — the Inlet electromagnetic valve 14 — the Pump 15 — the Control valve 16 — It is activated 17 — the Electromotor 18 — the Wheel cylinder 19 — the Final electromagnetic valve 20 — the Port is closed 21 — Deaktivirovan 22 — the Tank

Hydromodulator VDC functioning in a mode of increase of pressure at the squeezed out pedal of a foot brake (on an example of a contour of one wheel)


1 — Tank GTTS 2 — ГТЦ 3 — the pressure Gauge 4 — the Port is opened 5 — the Port is closed 6 — the Soaking up electromagnetic valve 7 — Otsechnoj the electromagnetic valve 8 — the Control valve 9 — Deaktivirovan 10 — Deaktivirovan 11 — Dempfernaja the chamber	12 — the Port is opened 13 — the Inlet electromagnetic valve 14 — the Pump 15 — the Control valve 16 — Deaktivirovan 17 — the Electromotor 18 — the Wheel cylinder 19 — the Final electromagnetic valve 20 — the Port is closed 21 — Deaktivirovan 22 — the Tank

Hydromodulator VDC functioning in a mode of increase of pressure at the released pedal of a foot brake (on an example of a contour of one wheel)


1 — Tank GTTS 2 — ГТЦ 3 — the pressure Gauge 4 — the Port is closed 5 — the Port is opened 6 — the Soaking up electromagnetic valve 7 — Otsechnoj the electromagnetic valve 8 — the Control valve 9 — It is activated 10 — It is activated 11 — Dempfernaja the chamber	12 — the Port is opened 13 — the Inlet electromagnetic valve 14 — the Pump 15 — the Control valve 16 — Deaktivirovan 17 — the Electromotor 18 — the Wheel cylinder 19 — the Final electromagnetic valve 20 — the Port is closed 21 — Deaktivirovan 22 — the Tank

Hydromodulator VDC functioning in a mode of deduction of pressure at the released pedal of a foot brake (on an example of a contour of one wheel)


1 — Tank GTTS 2 — ГТЦ 3 — the pressure Gauge 4 — the Port is closed 5 — the Port is opened 6 — the Soaking up electromagnetic valve 7 — Otsechnoj the electromagnetic valve 8 — the Control valve 9 — It is activated 10 — Reduktsionnyj the valve 11 — It is activated 12 — Dempfernaja the chamber	13 — the Port is closed 14 — the Inlet electromagnetic valve 15 — the Pump 16 — the Control valve 17 — It is activated 18 — the Electromotor 19 — the Wheel cylinder 20 — the Final electromagnetic valve 21 — the Port is closed 22 — Deaktivirovan 23 — the Tank

Hydromodulator VDC functioning in a mode of dump of pressure at the released pedal of a foot brake (on an example of a contour of one wheel)


1 — Tank GTTS 2 — ГТЦ 3 — the pressure Gauge 4 — the Port is closed 5 — the Port is opened 6 — the Soaking up electromagnetic valve 7 — Otsechnoj the electromagnetic valve 8 — the Control valve 9 — It is activated 10 — Reduktsionnyj the valve 11 — It is activated 12 — Dempfernaja the chamber	13 — the Port is closed 14 — the Inlet electromagnetic valve 15 — the Pump 16 — the Control valve 17 — It is activated 18 — the Electromotor 19 — the Wheel cylinder 20 — the Final electromagnetic valve 21 — the Port is opened 22 — It is activated 23 — the Tank

System VDC represents system with return the communication, allowing to keep course stability at vehicle movement in various modes (full or partial braking, movement накатом, dispersal, braking by the engine, change of loadings, performance of extreme maneuvers and so forth) VDC it is united with ABS and антипробуксовочной the monitoring system/monitoring system (TCS), logically developing advantages given by them.

The scheme of placing of components VDC and adjacent systems is presented on an illustration.

System VDC anticipates "advancing" or "delay" of an input of the car in turn at movement on roads with a slippery covering. The module of management VDC reveals intentions of the driver on fulfilment of maneuvers on the basis of the analysis of the information arriving from gauges of an angle of rotation of a steering wheel, brake pressure, tracing of working parametres of the power unit and so forth Simultaneously, being guided by indications of gauges ABS, cross-section overloads (G), the withdrawing moment and so forth, the system estimates reaction of the car to actions of the driver. Comparing the arriving information with put in memory of the processor in base parametres, the management module reveals tendencies to the drifts connected with insufficiency or excessiveness of sensitivity of a vehicle, and in due time provides creation of counteracting efforts at the expense of individual activation of brake mechanisms, updatings of traction effort of the engine and management of connection of a full drive (through TCM automatic transmission), i.e., activating corresponding functions ABS and TCS.

Principle of functioning VDC

Suppression of "excessive" reaction of the car turn of a wheel ("advancing")

At the moment of the beginning of withdrawal (drift) of a back part of the car as a result of excessive reaction to turn of a wheel the module of management VDC activates wheel cylinders of brake mechanisms of both external wheels that leads to occurrence of the force counteracting the withdrawing moment.

Suppression of "insufficient" reaction of the car on turn of a wheel ("delay")

If at a car input in turn the redock starts to withdraw to (take down) in a course direction, the module of management VDC activates brake mechanisms of both "internal" wheels, creating the force of the reaction compensating connected with pulling down передка withdrawing moment.

The module of management VDC

On the basis of the data arriving from corresponding information gauges, the module exercises administration of hydromodulator VDC functioning, and also makes activation of separate devices ABS and антипробуксовочной monitoring systems/monitoring systems (TCS).

Data exchange of the module of management VDC with TCM automatic transmission and the gauge of turn of a steering wheel is carried out on tyre CAN.

In case of revealing of infringements of serviceability of functioning VDC the management module provides switching-off of system and activation of a corresponding control lamp on an instrument guard of the car. Codes of the revealed refusals remain in memory of the processor.

Hydromodulator VDC

The hydromodulator at the command of the management module provides activation of pump assemblage and switching of the electromagnetic valves supervising giving of a brake liquid to wheel cylinders.

Principle of functioning of the hydromodulator

Mode of normal braking (ABS it is not activated)

In a mode of normal braking any of electromagnetic valves is not activated (ports inlet and отсечного valves are opened, final and soaking up - are closed). Developed in ГТЦ the pressure of a hydraulic liquid completely is transferred to the wheel cylinder through open ports отсечного and inlet valves.

Mode of dump of pressure at the squeezed out pedal of a foot brake

Inlet and final electromagnetic valves are activated, all other - is not present. Thus, ports of inlet and soaking up valves are closed, final and отсечного - are opened. In spite of the fact that pressure ГТЦ is transferred through open port of the soaking up valve, the further distribution pressure blocked by the closed inlet valve, on the other hand, while the port of the final valve is opened, the brake liquid freely flows from the wheel cylinder in the tank that leads to dump of hydraulic pressure and easing of brake effort.

From the tank the brake liquid is pumped over by the pump back in ГТЦ.

Mode of deduction of pressure at the squeezed out pedal of a foot brake

In the given mode only inlet electromagnetic valve, i.e. ports of all valves except отсечного is activated are closed. The pressure of a liquid from ГТЦ through open port отсечного the valve moves on the inlet valve, but does not pass further. As the port of the final valve also is closed, pressure continues to be kept in the wheel cylinder.

During all cycle of the given mode the pump continues to work on commands of the module of management VDC.

Mode of increase of pressure at the squeezed out pedal of a foot brake

All electromagnetic valves деактивированы, as well as in a mode of normal braking. The pressure of a hydraulic liquid from ГТЦ through open ports отсечного and inlet valves is transferred in the wheel cylinder, providing pressure increase.

The pump continues to work on commands of the module of management VDC during all cycle.

Mode of increase of pressure at the released pedal of a foot brake

In the given mode are activated only отсечной and soaking up valves, inlet and final remain деактивированными. Thus, ports отсечного and final valves are closed, inlet and отсечного - are opened also the pump provides перекачивание a brake liquid from tank GTTS in the wheel cylinder through open ports of soaking up and inlet valves that leads to activation of the brake mechanism.

Mode of deduction of pressure at the released pedal of a foot brake

All electromagnetic valves, except the final are activated. Thus, ports of all valves, except soaking up are closed. The pump provides перекачивание a brake liquid of tank GTTS through open port of the soaking up valve, however further the section of a path through passage is blocked by the closed port of the inlet valve. The closed port of the final valve prevents pressure dump in the wheel cylinder, moreover, at the expense of functioning of the pump it continues to grow, as the port of the inlet valve remains closed. At achievement by pressure of some certain size there is an opening built in assemblage отсечного the valve редукционной the assemblages, providing return of surplus of a liquid back in tank GTTS.

Mode of dump of pressure at the released pedal of a foot brake

All electromagnetic valves are activated, i.e., ports отсечного and the inlet valve are closed, soaking up and final - are opened. Thus the pump provides a fence of a brake liquid from the tank and its giving to ГТЦ through open port of the soaking up valve. As the inlet valve is closed, the liquid does not get to the wheel cylinder while its outflow from the cylinder in the tank is provided through open port of the final valve. As a result pressure in the wheel cylinder is dumped. From the tank the brake liquid is pumped over to ГТЦ through the open soaking up valve. Thus the pressure of a liquid submitted the pump on closed отсечной the valve continues to grow and on reaching limiting admissible value is dumped through редукционную assemblage in tank GTTS.

The gauge of turn of a steering wheel

The gauge gives out the information on a direction and size of an angle of rotation of a steering wheel on the module of management.

The gauge of cross-section overloads (G) and the withdrawing moment

On the basis of the information arriving from the gauge the module of management VDC estimates reaction of the car to actions of the driver at performance of maneuvers.

Wheel gauges ABS

Gauges ABS carry out the regular function under the control of frequency of rotation of turns of each of car wheels.

The engine management module (ECM)

ECM exercises in engine administration in target parametres according to the data arriving from the module of management VDC, and also delivers on last the information on current working parametres and turns of the power unit.

The module of management АТ (TCM)

TCM exercises administration муфтами couplings АТ, correcting traction effort according to the data arriving from the module of management VDC.

Control lamp ABS

The control lamp serves for the prevention of the driver of refusals of system of antiblocking of brakes (ABS).

Control lamp VDC

The given control lamp warns the driver about malfunctions in systems of dynamic stabilisation (VDC) and TCS.

The alarm indicator of activation VDC

Being activated in flashing (VDC) or constant (TCS) a mode, the indicator warns the driver about operation of corresponding system.

The alarm indicator of switching-off VDC (VDC OFF)

The indicator is activated at compulsory switching-off of systems VDC/TCS at the command of the user.

The switch of deactivation VDC

The switch is located on console section of the panel of devices under assemblage by a radio receiver and allows the driver to make time compulsory switching-off of system of dynamic stabilisation.

Switching-off VDC is possible only at speeds of movement of the car below 60 km/h (38 miles/ch).

Keeping of the button of switch VDC pressed within more than 10 seconds leads to switching-off of the alarm indicator «VDC OFF» then the button is blocked also using by it becomes possible only after engine restart.

Automatic activation of disconnected system VDC occurs at increase of speed of movement of the car to 60 km/h (38 miles/ch).

Necessity for switching-off VDC when defined пробуксовывание wheels it appears useful, can arise in following cases:

a) At a start of motion on road ice-covered or going abruptly uphill;
b) At attempts to get out of a dirt or a snowdrift in a case увязания all four wheels.

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