Downhill speed control
Your vehicle may be equipped with a downhill speed control feature, which helps to support braking when driving downhill in vehicles with automatic or DSG® transmission . The system uses the braking power of the engine.
The transmission selects the best gear for the circumstances, depending on the downhill slope and the current speed. The selector lever must be in position D/S . Downhill speed control is not active in Tiptronic mode .
The downhill speed control feature can shift down only as far as third gear, so it may be necessary to activate the Tiptronic mode when driving down very steep hills. When in Tiptronic mode, select second or first gear manually to use the braking power of the engine and relieve the load on the brakes.
If downhill speed control is active, the Start-stop system is automatically deactivated .
Downhill speed control activates automatically if all of the following conditions apply:
- The downhill slope is greater than about 6%.
- AND: The selector lever is in position D/S.
- AND (when the cruise control or Adaptive Cruise Control (ACC) is switched off): The vehicle speed is less than about 50 mph (80 km/h) or the brake pedal is depressed.
- AND (when the cruise control or Adaptive Cruise Control (ACC) is active): The stored speed is exceeded.
Downhill speed control deactivates automatically if one of the following occurs:
- The downhill slope is less than about 6%.
- OR: The transmission shifts up to a higher gear because the engine speed is faster than about 4,500 rpm.
- OR (when the cruise control or Adaptive Cruise Control (ACC) is active): The stored speed can be maintained.
WARNING
The intelligent technology of the downhill speed control feature cannot overcome the laws of physics and system-related limits. Never let the increased convenience provided by the downhill speed control feature tempt you into taking risks.
- Always adjust your speed, driving style, and the distance you keep between you and the vehicles ahead of you to the road, traffic, weather, and visibility conditions.
- Unintended vehicle movement can cause serious personal injury.
- The downhill speed control feature is not a substitute for careful and attentive driving.
- The downhill speed control feature cannot slow the vehicle down in all situations (for example, if the ground is slippery or icy).
- Always be prepared to take full control of the vehicle at all times.
WARNING
Always be ready to apply the brakes. Otherwise accidents and injuries can occur.
- The downhill speed control feature is merely a driving aid and cannot always slow the vehicle down enough on all downhill grades.
- The vehicle may pick up speed even though the downhill speed control feature is active.
WARNING
Driving with too little fuel in the fuel tank increases the risk of stalling, especially when driving up and down hills.
- If your vehicle stalls suddenly, this can cause an accident and serious personal injuries.
- Driver assistance and braking assistance systems can malfunction when there is too little fuel in the tank and cause you to lose control of the vehicle.
- Never drive until the fuel tank is almost empty.
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