System Description

The hill descent control system will help maintain vehicle speed when driving on steeper downhill grades. Hill descent control will provide braking allowing the driver to concentrate on steering while reducing the burden of brake and accelerator operation.
To operate the system, push the hill descent control switch. The hill descent control indicator in the combination meter will turn on.
Hill start assist function is only for the start aid. It maintains the brake fluid pressure for approx. 2 seconds after releasing the brake pedal, and then decreases the pressure gradually. If the vehicle starts by the accelerator operation, the brake is released automatically and a smooth start can be performed.
Fail-safe function is adopted. When a malfunction occurs in hill start assist function, the control is suspended for VDC function, TCS function, hill start assist function and Brake force distribution function. The vehicle status becomes the same as models without VDC function, TCS function, hill start assist function and Brake force distribution function. However, ABS function and EBD function are operated normally. Refer to Fail-safe .

SYSTEM DIAGRAM

Courtesy of NISSAN

INPUT SIGNAL AND OUTPUT SIGNAL

Major signal transmission between each unit via communication lines is shown in the following table:

Component	Signal description
Yaw rate/side/decel G sensor	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via communication line *: Yaw rate signal Side G sensor signal Decel G sensor signal
ECM	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication: Accelerator pedal position signal Engine speed signal Mainly receives the target throttle position signal from ABS actuator and electric unit (control unit) via CAN communication.
TCM	Mainly transmits the shift position signal to ABS actuator and electric unit (control unit) via CAN communication.
Combination meter	Mainly transmits the following signals to ABS actuator and electric unit (control unit) via CAN communication: Brake fluid level switch signal Parking brake switch signal Mainly receives the following signals from ABS actuator and electric unit (control unit) via CAN communication: VDC warning lamp signal VDC OFF indicator lamp signal

*: Communication line between yaw rate/side/decel G sensor and ABS actuator and electric unit (control unit)