Volvo XC60: Hill Descent Control (HDC)

Introduction

Normally, when the accelerator pedal is released while driving down hills, the vehicle's speed slows as the engine runs at lower rpm (the normal engine braking effect). However, if the downhill gradient becomes steeper and if the vehicle is carrying a load, speed increases despite the engine braking effect. In this situation, the brakes must be applied to reduce the vehicle's speed.

HDC is a type of automatic engine brake and makes it possible to increase or decrease the vehicle's speed on downhill gradients using only the accelerator pedal, without applying the brakes. The brake system functions automatically to maintain a low and steady speed.

HDC is particularly useful when driving down steep hills with rough surfaces, and where the road may have slippery patches.

WARNING
HDC does not function in all situations, and is a supplementary braking aid. The driver has full responsibility for driving in a safe manner.

Function

• HDC can be switched on and off with the button in the center console. An indicator light in the button illuminates when HDC is activated.

• The indicator light in the instrument panel illuminates and a message is displayed when the system is controlling the vehicle's speed.

• HDC only functions when first or reverse gears are selected (1 will be shown in the instrument panel display when first gear is selected).

NOTE
HDC cannot be activated if the gear selector is the D position.

Using HDC

HDC allows the car to roll forward at a maximum speed of 6 mph (10 km/h), and 4 mph (7 km/h) in reverse. However, the accelerator pedal can be used to select any speed that is possible in first or reverse gears. When the accelerator pedal is released, speed is quickly reduced again to 6 mph (10 km/h) or 4 mph (7 km/h), depending on the gear selected, regardless of the hill's gradient. It is not necessary to apply the brakes.

• The brake lights illuminate automatically when HDC is controlling the vehicle's speed.

• The driver can slow or stop the vehicle at any time by applying the brakes.

HDC is deactivated when:
• The button on the center console is pressed
• A gear higher than first gear is selected
• D is selected on vehicles with an automatic transmission

HDC can be deactivated at any time. If this is done while driving down a steep hill, the system's braking effect will decrease gradually.

NOTE
Engine response to pressure on the accelerator pedal may be slightly slower than normal when HDC is activated.

Parking brake

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