2009 Nissan Xterra Owner's Manual - Page 225

This procedure is described in the vehicle service manual and can be performed by a NISSAN dealer. ANTI-LOCK BRAKING SYSTEM (ABS) WARNING ● The Anti-lock Braking System (ABS) is a sophisticated device, but it cannot prevent accidents resulting from careless or dangerous driving techniques. It can help maintain vehicle control during braking on slippery surfaces. Remember that stopping distances on slippery surfaces will be longer than on normal surfaces even with ABS. Stopping distances may also be longer on rough, gravel or snow covered roads, or if you are using tire chains. Always maintain a safe distance from the vehicle in front of you. Ultimately, the driver is responsible for safety. ● Tire type and condition may also affect braking effectiveness. - When replacing tires, install the specified size of tires on all four wheels. - When installing a spare tire, make sure that it is the proper size and type as specified on the Tire and Loading Information label. See "Tire and Loading Information label" in the "Technical and consumer information" section of this manual. - For detailed information, see "Wheels and tires" in the "Maintenance and do-it-yourself" section of this manual. The Anti-lock Braking System (ABS) controls the brakes so the wheels do not lock during hard braking or when braking on slippery surfaces. The system detects the rotation speed at each wheel and varies the brake fluid pressure to prevent each wheel from locking and sliding. By preventing each wheel from locking, the system helps the driver maintain steering control and helps to minimize swerving and spinning on slippery surfaces. WARNING Do not pump the brake pedal. Doing so may result in increased stopping distances. Normal operation The ABS operates at speeds above 3 - 6 MPH (5 - 10 km/h). When the ABS senses that one or more wheels are close to locking up, the system electronically controls the pressure applied to each brake. This action is similar to pumping the brakes very quickly. You may feel a pulsation in the brake pedal and hear a noise from under the hood or feel a vibration from the actuator when it is operating. This is normal and indicates that the ABS is operating properly. However, the pulsation may indicate that road conditions are hazardous and extra care is required while driving. Using the system Depress the brake pedal and hold it down. Depress the brake pedal with firm steady pressure, but do not pump the brakes. The ABS will operate to prevent the wheels from locking up. Steer the vehicle to avoid obstacles. Self-test feature The ABS includes electronic sensors, electric pumps, hydraulic solenoids and a computer. The computer has a built-in diagnostic feature that tests the system each time you start the engine and move the vehicle at a low speed in forward or reverse. When the self-test occurs, you may hear a "clunk" noise and/or feel a pulsation in the brake Starting and driving 5-33