System Description

SYSTEM DIAGRAM 

Courtesy of NISSAN NORTH AMERICA, INC.

OUTLINE 

• BCM incorporates a power saving control function that reduces the power consumption according to the vehicle status.
• BCM switches the status (control mode) by itself with the power saving control function. It performs the sleep request to each unit (IPDM E/R, combination meter, TCU, driver seat control unit, pre-crash seat belt control unit, CAN gateway and steering force control module) that operates with the ignition switch OFF.

  Normal mode (wake-up)

  • CAN communication is normally performed with other units
  • Each control with BCM is operating properly

  CAN communication sleep mode (CAN sleep)

  • CAN transmission is stopped
  • Control with BCM only is operating

  Low power consumption mode (BCM sleep)

  • Low power consumption control is active
  • CAN transmission is stopped

LOW POWER CONSUMPTION CONTROL WITH BCM 

BCM reduces the power consumption with the following operation in the low power consumption mode.

• The reading interval of the each switches changes from 10 ms interval to 60 ms interval.

Sleep mode activation 

• BCM receives the sleep-ready signal (ready) from IPDM E/R and TCU via CAN communication.
• BCM transmits the sleep wake up signal (sleep) to each unit when all of the CAN sleep conditions are fulfilled.
• Each unit stops the transmission of CAN communication with the sleep wake up signal. BCM is in CAN communication sleep mode.
• BCM is in the low power consumption mode and perform the low power consumption control when all of the BCM sleep conditions are fulfilled with CAN sleep condition.

Wake-up operation 

• BCM transmits sleep wake up signal (wake up) to each unit when any condition listed below is established, and then goes into normal mode from low power consumption mode.
• Each unit starts transmissions with CAN communication by receiving sleep wake up signals. Each unit transmit wake up signals to BCM with CAN communication to convey the start of CAN communication.