- Fig. 1 Top of centre console: Button for downhill assist function
- Fig. 2 Instrument cluster: Downhill assist function
The downhill assist function helps you to drive down steep gradients at a constant speed.
To switch on the downhill assist function, press the button 
in the centre console Fig. 1 or next to the selector gate. The LED in the button will light up.
in the centre console Fig. 1 or next to the selector gate. The LED in the button will light up.Press the button again to switch off the downhill assist function. The LED in the button will go out.
The downhill assist function limits the speed both when driving forwards and reversing on gradients of up to 50% by automatically braking all four wheels. The anti-lock brake system remains activated so the wheels are prevented from locking up. On vehicles with manual gearbox, the downhill assist function adapts the engine's speed so that it does not drop below the idling speed of the engine.
When the downhill assist function is switched on, it maintains the current speed when you start a descent. The system can only be switched on when driving below approx. 60 km/h. The driving speed is controlled to between 4 and 30 km/h. On vehicles with a manual gearbox, the downhill assist function will only maintain the speed at levels below approx. 9 km/h if you keep your foot on the clutch or select neutral gear. If you release the clutch with the vehicle in gear at a speed of less than approx. 9 km/h, the target speed will be increased. You can increase or reduce the speed within this range anytime by pressing the accelerator or brake pedal. The system also makes the vehicle easier to steer when reversing by optimising the brake force distribution.
It is important that the surface is able to provide sufficient grip. For example, the downhill assist cannot perform its function on an icy or slippery slope WARNING!.
The system will not control the driving speed when you are driving between approx. 30 and 60 km/h. The system is then in standby mode. This is indicated by the lit LED in the button. The system is automatically switched off and the LED goes out once the speed exceeds 60 km/h.
The instrument cluster display indicates whenever the driving speed is being actively controlled to a certain speed up to approx. 30 km/h Fig. 2. Two dashes "--" will appear when the system goes into standby mode.
The downhill assist function is activated automatically if the following conditions are met:
- The LED in the button must be lit.
- The driving speed must be lower than approx. 30 km/h.
- The gradient must be approx. 10%.
- It is essential that you adjust your speed to suit the weather, road and traffic conditions. Do not let the extra safety provided tempt you into taking any risks when driving – this can cause accidents.
- The downhill assist function is not able to overcome the physical limits of adhesion. Therefore it is important that you always drive at a safe speed for the prevailing conditions and traffic situation.
- The downhill assist function cannot keep your vehicle's speed constant under all circumstances when you are driving down a hill (e.g. if the road is slippery) and cannot replace the full concentration of the driver.