VDC FUNCTION: System Description

Side slip or tail slip may occur while driving on a slippery road or intending an urgent evasive driving. VDC function detects side slip status using each sensor when side slip or tail slip is about to occur and improves vehicle stability by brake control and engine output control during driving.
In addition to ABS function, EBD function and TCS function, target side slip amount is calculated according to steering operation amount from steering angle sensor and brake operation amount from pressure sensor. By comparing this information with vehicle side slip amount that is calculated from information from yaw rate/side/decel G-sensor and wheel sensor, vehicle driving conditions (conditions of understeer or oversteer) are judged and vehicle stability is improved by brake force control on all 4 wheels and engine output control.

Fig 1: VDC Control Schematic Diagram
Courtesy of NISSAN NORTH AMERICA, INC.
Control unit portion automatically improves driving stability by performing brake force control as well as engine output control, by transmitting drive signal to actuator portion according to difference between target side slip amount and vehicle side slip amount
VDC function can be switched to non-operational status (OFF) by operating VDC OFF switch. In this case, VDC OFF indicator lamp turns ON.
VDC function is not operate when 4WD mode is "4L". (Models with 4WD system)
VDC warning lamp blinking while VDC function is in operation and indicates to the driver that the function is in operation.
Slight vibrations are felt on the brake pedal and the operation noises occur, when VDC function operates. This is not a malfunction because it is caused by VDC function that is normally operated.
CONSULT can be used to diagnose the system diagnosis.
Fail-safe function is adopted. When a malfunction occurs in VDC function, the control is suspended for VDC function, TCS function, hill start assist function and brake limited slip differential (BLSD) function. The vehicle status becomes the same as models without VDC function, TCS function, hill start assist function and brake limited slip differential (BLSD) function. However, ABS function and EBD function are operated normally. Refer to "FAIL-SAFE ".
NOTE: VDC has the characteristic as described here, but it is not the device that helps reckless driving.