System overview: Introduction

The Mark 20 brake control system 

The Mark 20 brake control system is an electronic control system which prevents wheel lock up during braking (ABS). As the ABS system prevents the wheels from locking, steering control is maintained and the maximum braking effect is transferred to the road surface.

The brake control system is equipped with:

• ABS (Anti-lock Braking System)
• Electronic Brake force Distribution function, which regulates the brake force to the rear wheels.

The brake control system, as a factory installed option, can be supplemented with:

• STC (Stability and Traction Control)
• TRACS (TRAction Control System)
• DSTC (Dynamic Stability and Traction Control).

EBD 

EBD (Electrical Brake force Distribution) is a function for electronically controlling the brake force on the rear wheels and is integrated with the ABS system. During electronic brake force distribution (EBD) control, the control module regulates the hydraulic pressure in the brake circuit for the rear wheels if the rear wheels tend to lock under braking. This ensures optimal and stable braking. The EBD function replaces the relief valve used in the Mark IV version to reduce the pressure in the brake circuit for the rear wheels.

TRACS 

TRACS is a traction control system which is integrated with the ABS system. The traction control system distributes driven power between the wheels so that the wheel with the best road traction receives the greatest amount of driven power. The system is mainly designed to assist with moving off on slippery surfaces at speeds up to approximately 40 km/h. TRACS has only a very limited effect at speeds over 40 km/h. TRACS (traction control system) is always engaged when the ignition is switched on. TRACS (traction control system) is engaged and disengaged using a switch in the lower section of the climate control module (CCM).

STC 

STC (stability and traction control) consists of two components:

• Traction Control - this function is described above under TRACS. The traction control function is always engaged when the ignition is switched on. The traction control function together with the stability function is engaged and disengaged using a switch under the climate control module (CCM)
• Stability Control - stability system which is integrated in the ABS system and stabilizes the car in the event of wheel spin. The Anti-lock Brake System Module (ABS) transmits a signal to the engine control module (ECM) to reduce engine torque until the slipping wheel(s) has/have stopped spinning. The stability function is always engaged when the ignition is switched on. The stability function together with the traction control function is engaged and disengaged using a switch in the lower section of the climate control module (CCM). Applies to cars equipped with STC (stability and traction control).

DSTC 

DSTC (Dynamic Stability and Traction control) - a dynamic anti-slip system which is integrated in the STC (stability and traction control) system. The DSTC (dynamic stability and traction control) function is always engaged when the ignition is switched on but can be disengaged or engaged manually using the switch in the lower section of the climate control module (CCM).

The DSTC (Dynamic stability and traction control) system consists of the following:

• Traction Control - This function is described above under TRACS
• Stability Control - Described under STC above
• AYC (Active Yaw Control). The system is based upon a number of sensors which sense the driver's steering movements (steering wheel angle) and the directional, both straight and lateral, movement of the car. The information is used to correct the car in the event of oversteer or understeer.