Other Functions

The Mark 25E1 brake system also includes a number of functions to assist the driver in various braking situations.

Brake assistance 

Emergency brake assistance (EBA) is a function that helps the driver obtain maximum braking effect in an emergency situation. The brake control module (BCM) monitors the pressure in the brake servo with the help of a pressure sensor in the hydraulic unit. Quick movement of the brake pedal (emergency braking) generates a rapid change of pressure in the brake servo. When the control module registers the pressure change, the brake system activates the hydraulic pump. The hydraulic pump increases brake pressure in the brake system to obtain optimum braking effect (more powerful than during normal braking). Full braking effect is maintained as long as the driver maintains or increases pressure on the brake pedal. The function ceases immediately if the driver releases the brake pedal. The function is active from approx. 10 km/h (6 mph) to top speed. The function cannot be disengaged.

Hill descent control (only XC70 AWD) 

Hill Descent Control (HDC) is a function to help the driver handle the vehicle when driving "off-road".

For manual transmissions the function is active in 1st gear as well as reverse gear (R). For automatic transmissions the function is active in 1st gear on the condition that Geartronic is used and when reverse gear (R) is selected. The function brakes the vehicle automatically without the driver stepping on the brake pedal. The characteristics for the throttle pedal change as well.

The function is activated with a switch on lower part of Climate control module (CCM). The function can be activated and deactivated manually. The switch has a visual green LED-indicator which shows position ON  . When the function is activated and deactivated, this is confirmed with a message in Driver information module (DIM).

HSA- Hill Start Assist (only vehicles with transmission MPS6) 

HSA (Hill start assist) is a function to help the driver when starting on a hill.

The function prevents unwanted vehicle movement from the time that the driver releases the brake pedal and presses down the throttle pedal. The function is active in position D (to prevent the vehicle from rolling backward) as well as in position R (to prevent the vehicle from rolling forward).

In order for the function to engage, the incline of the slope must be at least 4%. After the brake pedal has been released, brake pressure is maintained for 1.5-2 seconds.

A triggering factor is needed for self-induced oscillations to arise, for example: 

• vehicle with trailer is exposed to sudden forceful sidewind
• vehicle with trailer is driven on uneven road or on a bump
• sweeping steering wheel movements.

Trailer stability assistance (TSA) continuously monitors the car's movement, especially sideways. If self-induced oscillations occur, individual brake control takes place on the wheels, having a stabilizing effect on the vehicle. Often this is enough to regain control of the vehicle. If self-induced oscillations are not reduced, the vehicle is braked on all wheels combined with reduction of the engine's drive power. During this phase, normally the brake lights are on, this is determined by how 'big' the braking is. When self-induced oscillations have stopped and the vehicle is stable once again, trailer stability assistance stops its control and the driver regains full control of the car.

Actions from trailer stability assistance (TSA) may not occur if the driver tries to counteract self-induced oscillations with forceful steering wheel movements, since trailer stability assistance (TSA) cannot decide if it is the driver or the trailer that is causing the self-induced oscillations. Trailer stability assistance (TSA) can act in the speed range 60-160 km/h.

When trailer stability assistance (TSA) is working the DSTC-symbol flashes in the combination instrument.