2005 Jeep Grand Cherokee Owner Manual - Page 246

246 STARTING AND OPERATING To release the parking brake, pull up slightly, press the center button, then lower the lever completely. Be sure the parking brake is fully disengaged before driving. Failure to do so can lead to brake failure. NOTE: Parking brake adjustment and maintenance should be performed by your authorized dealer. ANTI-LOCK BRAKE SYSTEM The Anti-Lock Brake System (ABS) is designed to aid the driver in maintaining vehicle control under adverse braking conditions. The system operates with a separate computer to modulate hydraulic pressure to prevent wheel lock-up and help avoid skidding on slippery surfaces. All vehicle wheels and tires must be the same size and type and tires must be properly inflated to produce accurate signals for the computer. WARNING! Significant over or under inflation of tires, or mixing sizes of tires or wheels on the vehicle can lead to loss of braking effectiveness. The Anti-Lock Brake System conducts a low-speed selftest at about 12 mph (20 km/h). If you have your foot lightly on the brake while this test is occurring you may feel slight pedal movement. The movement can be more apparent on ice and snow. This is normal. The Anti-Lock Brake System pump motor runs during the self-test at 12 mph (20 km/h) and during an ABS stop. The pump motor makes a low humming noise during operation, which is normal.