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 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.