2010 Nissan Armada Owner's Manual - Page 364

VEHICLE DYNAMIC CONTROL (VDC) SYSTEM WARNING Do not pump the brake pedal. Doing so may result in increased stopping distances. pedal. This is normal and does not indicate a malfunction. If the computer senses a malfunction, it switches the ABS off and illuminates the ABS warning light on the instrument panel. The brake system then operates normally, but without anti-lock assistance. If the ABS warning light illuminates during the self-test or while driving, have the vehicle checked by a NISSAN dealer. The Vehicle Dynamic Control (VDC) system uses various sensors to monitor driver inputs and vehicle motion. Under certain driving conditions, the VDC System helps to perform the following functions: ● Controls brake pressure to reduce wheel slip on one slipping drive wheel so power is transferred to a non slipping drive wheel on the same axle. ● Controls brake pressure and engine output to reduce drive wheel slip based on vehicle speed (traction control function). ● If the 4WD transfer case is shifted into 4LO indicator light will come on and the the VDC system will be turned off. See "Using Four Wheel Drive (4WD)" earlier in this section. ● Controls brake pressure at individual wheels and engine output to help the driver maintain control of the vehicle in the following conditions: - understeer (vehicle tends to not follow the steered path despite increased steering input) - oversteer (vehicle tends to spin due to certain road or driving conditions) Normal operation The ABS operates at speeds above 3 - 6 MPH (5 - 10 km/h). The speed varies according to road conditions. When the ABS senses that 1 or more wheels are close to locking up, the actuator rapidly applies and releases hydraulic pressure. 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. 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 5-31