2003 Pontiac Aztek Owner's Manual - Page 335

Brake Wear Your vehicle has four-wheel disc brakes. With the wrong kind of fluidin your brake system, your brakes may not work well, or they may not even work at all. This could cause a crash. Always use the proper brake fluid. Notice: Disc brake pads have built-in wear indicators that make a high-pitched warning sound when the brake pads are worn and new pads are needed. The sound may come and go or be heard all the time your vehicle is moving (except when you are pushing on the brake pedal firmly). Using the wrong fluid can badly damage brake system parts. For example, just a few drops of mineral-based oil, such as engine oil, in your brake system can damage brake system parts so badly that they'll have to be replaced. Don't let someone put in the wrong kind of fluid. * If you spill brake fluid on your vehicle's painted surfaces, the paint finish can be damaged. Be careful not to spill brake fluid on your vehicle. If you do, wash it off immediately. See "Appearance Care'' in the Index. The brake wear warning sound means that soon your brakes won't work well. That could lead to an accident.When you hear the brake wear warning sound, have your vehicle serviced. I Notice: Continuing to drive with worn-out brake pads could result in costly brake repair. Some driving conditions or climates may cause a brake squeal when the brakes are first applied or lightly applied. This does not mean something is wrong with your brakes. 5-40