Nissan Sentra B18 (2020-2025) Service Manual: System

Nissan Sentra B18 (2020-2025) Service Manual / Brakes / Brake Control System :: Rear Automatic Braking / System Description / System

System Description

System Description

SYSTEM DIAGRAM

Component	Function
ADAS control unit 2	ADAS Control Unit 2
ECM	Component Description
TCM	TCM
Steering angle sensor	Steering Angle Sensor
Combination meter	Combination Meter(4.2 inch Information Display) or Combination Meter(7 inch Information Display)
ABS actuator and electric unit (control unit)	ABS Actuator and Electric Unit (Control Unit)
Stop lamp switch	Stop Lamp Switch
Driver assistance buzzer	Driver Assistance Buzzer
Sonar control unit	Sonar Control Unit

ADAS CONTROL UNIT 2 INPUT/OUTPUT SIGNAL ITEM

Input Signal Item

Transmit unit	Signal name		Description
ECM	CAN communication	Closed throttle position signal	Receives idle position state (ON/OFF)
		Accelerator pedal position signal	Receives accelerator pedal position (angle)
		Engine speed signal	Receives engine speed
		Stop lamp switch signal	Receives an operational state of the brake pedal
TCM^*	CAN communication	Input speed signal	Receives the number of revolutions of input shaft
		Current gear position signal	Receives a current gear position
		Shift position signal	Receives a selector lever position
		Output shaft revolution signal	Receives the number of revolutions of output shaft
ABS actuator and electric unit (control unit)	CAN communication	ABS malfunction signal	Receives a malfunction state of ABS
		TCS malfunction signal	Receives a malfunction state of TCS
		VDC malfunction signal	Receives a malfunction state of VDC
		Nissan Sentra Vehicle speed signal (ABS)	Receives wheel speeds of four wheels
		Brake fluid pressure signal	Receives brake fluid pressure
Steering angle sensor	CAN communication	Steering angle sensor signal	Receives the number of revolutions, turning direction of the steering wheel
Combination meter	CAN communication	System selection signal	Receives a selection state of each item in “Emergency Brake” selected with the combination meter
Sonar control unit	CAN communication	Sonar sensor signal	Receives obstacle information (existence & distance)

*: CVT models

Output Signal Item

Reception unit	Signal name		Description
ECM	CAN communication	Torque down request signal	Transmits a signal to control the engine torque.
ECM	CAN communication	Stop lamp request signal	Transmits a signal to activates the stop lamp.
ABS actuator and electric unit (control unit)	CAN communication	Brake fluid pressure control signal	Transmits a brake fluid pressure control signal to activates the brake
Combination meter	CAN communication	Meter display signal	Transmits a signal to display a state of the system on the information display
Combination meter	CAN communication	RAB warning lamp signal	Transmits a signal to illuminate RAB warning lamp Transmits an ON/OFF state of the RAB
Driver assistance buzzer	Driver assistance buzzer signal		Transmits a driver assistance buzzer signal to active the buzzer

FUNCTION DESCRIPTION

The Rear Automatic Braking system can assist the driver when the Nissan Sentra vehicle is backing up and approaching objects directly behind the vehicle.
When the shift lever is in the R (Reverse) position and the Nissan Sentra vehicle speed is less than approximately 15 km/h (7 MPH), the RAB system operates.
The RAB system detects obstacles behind the Nissan Sentra vehicle using the sonar sensors.
If a risk of a collision with an obstacle is detected when own Nissan Sentra vehicle is backing up, the RAB system warning indicator will flash in the vehicle information display, and the system will chime three times.
The system will then automatically apply the brakes.
Note:
- After the automatic brake application, the driver must depress the brake pedal to maintain brake pressure.
- Driver can temporarily cancel the sonar function in the Nissan Sentra vehicle, but the RAB system will continue to operate.

OPERATION DESCRIPTION

Sonar detects a object approaching, and transmits the object detection signal to ADAS control unit 2 via CAN communication.
The ADAS control unit 2 performs the following operations according to the degree of possibility of a collision.
- Transmits the driver assistance buzzer signal to the ADAS control unit 2 and sounds the warning system buzzer.
- Transmits the meter display signal to the combination meter and displays the RAB system warning indicator.
- Transmits the brake fluid pressure control signal to the ABS actuator and electric unit (control unit) via chassis control module and performs the brake control.
- Transmits the stop lamp request signal to ECM and turn ON the stop lamp.

Note:

ON/OFF of RAB system is performed with the combination meter.
The RAB system will be automatically turned ON when the engine is restarted.

Operation Condition

ADAS control unit 2 performs the control when the following conditions are satisfied.

When the RAB system setting on the combination meter is ON.
When the Nissan Sentra vehicle speed is below approximately 15 km/h (9 MPH).
There is a possibility of a collision with the object backward.

No Operation Condition

The ADAS control unit 2 is not operate when the system is under the conditions of the no operation condition.

When the RAB system setting on the combination meter is OFF.
When the Nissan Sentra vehicle speed is above approximately 15 km/h (9 MPH).
When the object backward is not detected

Operation Cancellation Condition

The ADAS control unit 2 cancels the operation when the system is under any conditions of the operation cancellation condition.

When the system judges that the Nissan Sentra vehicle comes to a standstill by the system control.
When the system malfunction occurs.
When the sonar area of the rear bumper is dirty and the measurement of the distance between the object becomes difficult.

Fail-Safe (adas Control Unit 2)

Fail-safe (ADAS Control Unit 2)

Refer to Fail-safe (ADAS Control Unit 2).

Warning Lamp/indicator Lamp

Warning Lamp/Indicator Lamp

Warning Lamp/Indicator Lamp

Name	Design	Function
RAB warning lamp		The RAB warning lamp warns the driver that RAB system is OFF. The RAB warning lamp warns the driver of a malfunction in the RAB system. For layout, Refer to Design(4.2 inch Information Display) or Design(7 inch Information Display)

Component Parts

Rear Automatic Braking System Component Parts Location Component Parts Location A. ...

Operation

4.2 Inch Information Display Operation Operation SWITCH NAME AND FUNCTION No. Switch name ...

Other materials:

Warning signals
To help prevent the vehicle from moving unexpectedly by erroneous operation of the Intelligent Key or to help prevent the vehicle from being stolen, a chime or buzzer sounds from inside and outside the vehicle and a warning light comes on in the instrument panel. When a chime or beep sounds ...

Diagnosis System (ipdm E/r)
Consult Function (ipdm E/r) CONSULT Function (IPDM E/R) IPDM E/R Refer to CONSULT Function (IPDM E/R). ...

Instrument panel
This instrument panel overview helps Nissan Sentra drivers quickly identify switches, displays, and controls essential for safe vehicle operation. Headlight/turn signal switch Steering wheel switch Audio controls Driver's supplemental air bag Horn Meters and gauges Warning ...