GM Service Manual Online
For 1990-2009 cars only

Your vehicle has a regenerative braking system. This system works whenever you take your foot off the accelerator pedal while your vehicle is moving in DRIVE (D). This causes your vehicle to slow down slightly faster. It may feel like the brake pedal is being pressed, even when it is not.

Regenerative braking takes some of the energy from the moving vehicle and turns it back into electrical energy. This energy is then stored back into the vehicle's 42-volt battery system, contributing to increased fuel efficiency.