GM Service Manual Online
For 1990-2009 cars only

See Brake System Warning Light.

Braking action involves perception time and reaction time. Deciding to push the brake pedal is perception time. Actually doing it is reaction time.

Average reaction time is about three-fourths of a second. But that is only an average. It might be less with one driver and as long as two or three seconds or more with another. Age, physical condition, alertness, coordination, and eyesight all play a part. So do alcohol, drugs, and frustration. But even in three-fourths of a second, a vehicle moving at 60 mph (100 km/h) travels 66 feet (20 m). That could be a lot of distance in an emergency, so keeping enough space between the vehicle and others is important.

And, of course, actual stopping distances vary greatly with the surface of the road, whether it is pavement or gravel; the condition of the road, whether it is wet, dry, or icy; tire tread; the condition of the brakes; the weight of the vehicle; and the amount of brake force applied.

Avoid needless heavy braking. Some people drive in spurts -- heavy acceleration followed by heavy braking -- rather than keeping pace with traffic. This is a mistake. The brakes might not have time to cool between hard stops. The brakes will wear out much faster with a lot of heavy braking. Keeping pace with the traffic and allowing realistic following distances eliminates a lot of unnecessary braking. That means better braking and longer brake life.

If the vehicle ever loses electrical power while it is being driven, brake normally but do not pump the brakes. If the brakes are pumped, the pedal could get harder to push down. If the vehicle loses electrical power, there will still be some power brake assist but it will be used when the brake is applied. Once the power assist is used up, it can take longer to stop, the brake pedal will be harder to push, and you might experience longer pedal travel.

Adding non-dealer/non-retailer accessories can affect vehicle performance. See Accessories and Modifications.

Hill Start Assist

This vehicle has a Hill Start Assist (HSA) feature, which may be useful when the vehicle is stopped on a grade. This feature is designed to prevent the vehicle from rolling, either forward or rearward, during vehicle drive off. After the vehicle is stopped on an incline, push the brake pedal completely to the floor to activate Hill Start Assist. When the system activates, a chime will sound and the HSA ON message will be displayed.

Letting off the brake pedal slightly or applying the accelerator pedal to disengage Hill Start Assist gives the driver two seconds to pull forward or back up before the vehicle starts to roll. Lightly ease off the brake pedal to disengage Hill Start Assist. The brakes will automatically be held for a maximum of two seconds while the driver switches from applying the brakes to pushing the accelerator pedal.

When Hill Start Assist is active, the driver might experience a "hard pedal." This is normal and does not affect safe brake operation.

On steeper hills, Hill Start Assist will only activate if the driver tries to move the vehicle up the hill. It will not activate if the vehicle is in a drive gear and facing downhill or if the vehicle is facing uphill and in R (Reverse).