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

Nissan Sentra B18 (2020-2025) Service Manual / Electrical & Power Control / Lan System :: Can / System Description / System

Can Communication System

System Description

System Description

SYSTEM DIAGRAM

DESCRIPTION

CAN (Controller Area Network) is a serial communication line for real time application. It is an on-Nissan Sentra vehicle multiplex communication line with high data communication speed and excellent error detection ability. Many electronic control units are equipped onto a Nissan Sentra vehicle, and each control unit shares information and links with other control units during operation (not independent). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.

The following control units connect to CAN communication circuits.

CAN communication circuit	Control unit	Reference
Between the following circuits Nissan Sentra Vehicle CAN communication 1 circuit Vehicle CAN communication 2 circuit Chassis CAN communication 1 circuit Chassis CAN communication 2 circuit Chassis CAN communication 3 circuit Drivetrain CAN communication circuit IT CAN communication circuit Diagnostic CAN communication circuit	8CH CAN gateway	System Description
Between the following circuits. Nissan Sentra Vehicle CAN communication 1 circuit Drivetrain CAN communication circuit Engine CAN communication circuit	ECM	System Description
Chassis CAN communication 1 circuit ⇔ Chassis CAN communication circuit 2 circuit	Chassis control module (with built in steering angle sensor)	System Description
Between the following circuits ITS CAN communication circuit Chassis CAN communication 2 circuit Chassis CAN communication 3 circuit	ADAS control unit 2	System Description

CAN COMMUNICATION SIGNAL GENERATION

Termination circuits (resistors) are connected across the CAN communication system. When transmitting a CAN communication signal, each control unit passes a current to the CAN-H line and the current returns to the CAN-L line.
The current flows separately into the termination circuits connected across the CAN communication system and the termination circuits drop voltage to generate a potential difference between the CAN-H line and the CAN-L line.
Note:
A signal with no current passage is called “Recessive” and one with current passage is called “Dominant”.
The system produces digital signals for signal communications, by using the potential difference.

THE CONSTRUCTION OF CAN COMMUNICATION SIGNAL (MESSAGE)

No.	Message name	Description
1	Start of frame (1 bit)	Start of message.
2	Arbitration of field (11 bit)	Priorities of message-sending are shown when there is a possibility that multiple messages are sent at the same time.
3	Control field (6 bit)	Signal quantity in data field is shown.
4	Data field (0-64 bit)	Actual signal is shown.
5	CRC field (16 bit)	The transmitting control unit calculates sending data in advance and writes the calculated value in a message. The receiving control unit calculates received data and judges that the data reception is normal when the calculated value is the same as the value written in the sent data.
6	ACK field (2 bit)	The completion of normal reception is sent to the transmitting unit.
7	End of frame (7 bit)	End of message.

CAN Communication Line

The CAN communication line is a twisted pair wire consisting of strands of CAN-H and CAN-L and has noise immunity.

Note:

The CAN communication system has the characteristics of noise-resistant because this system produces digital signals by using the potential difference between the CAN-H line and the CAN-L line and has the twisted pair wire structure.

Since the CAN-H line and the CAN-L line are always adjacent to each other, the same degree of noise occurs, respectively, when a noise occurs. Although the noise changes the voltage, the potential difference between the CAN-H line and the CAN-L line is insensitive to noise. Therefore, noise-resistant signals can be obtained.

CAN Signal Communications

Each control unit of the CAN communication system transmits signals through the CAN communication control circuit included in the control unit and receives only necessary signals from each control unit to perform various kinds of control.

Example: Transmitted signals
Example: Received signals

Note:

The above signal names and signal communications are provided for reference purposes. For CAN communications signals of this Nissan Sentra vehicle, refer to CAN Communication Signal Chart.

Can Communication Control Circuit

CAN Communication Control Circuit

CAN communication control circuit is incorporated into the control unit and transmits/receives CAN communication signals.

Component	System description
CAN controller	It controls CAN communication signal transmission and reception, error detection, etc.
Transceiver IC	It converts digital signal into CAN communication signal, and CAN communication signal into digital signal.
Noise filter	It eliminates noise of CAN communication signal.
Termination circuit^* (Resistance of approx. 120 Ω)	Generates a potential difference between CAN-H and CAN-L.

*: These are the only control units wired with both ends of CAN communication system.

Can System Specification Chart

CAN System Specification Chart

Determine CAN system type from the following specification chart

Note:

Refer to Trouble Diagnosis Flow Chart for how to use CAN system specification chart.


Body type	Sedan
Axle	2WD
Engine	MR20DD
Transmission	M/T	CVT
Brake control	VDC
Around view monitor system			X		X
Telematics system				X	X
CAN system type	1	2	3	4	5
Nissan Sentra Vehicle CAN communication 1 unit
ECM	X	X	X	X	X
ABS actuator and electric unit (control unit)	X	X	X	X	X
IPDM E/R	X	X	X	X	X
TCM		X	X	X	X
8CH CAN gateway	X	X	X	X	X
Air bag diagnosis sensor unit	X	X	X	X	X
EPS control unit	X	X	X	X	X
Intelligent Key unit	X	X	X	X	X
A/C auto amp.^1 A/C amp.^2	X	X	X	X	X
Combination meter	X	X	X	X	X
BCM	X	X	X	X	X
Nissan Sentra Vehicle CAN communication 2 unit
8CH CAN gateway	X	X	X	X	X
BOSE speaker amp.			X		X
Sonar control unit	X	X	X	X	X
ITS CAN communication unit
Front camera unit	X	X	X	X	X
ADAS control unit 2	X	X	X	X	X
Distance sensor	X	X	X	X	X
Chassis CAN communication 1 unit
8CH CAN gateway	X	X	X	X	X
ABS actuator and electric unit (control unit)	X	X	X	X	X
Chassis control module (with built in steering angle sensor)	X	X	X	X	X
Chassis CAN communication 2 unit
8CH CAN gateway	X	X	X	X	X
Distance sensor	X	X	X	X	X
Chassis control module (with built in steering angle sensor)	X	X	X	X	X
ADAS control unit 2	X	X	X	X	X
Front camera unit	X	X	X	X	X
Chassis CAN communication 3 unit
8CH CAN gateway	X	X	X	X	X
ADAS control unit 2	X	X	X	X	X
Around view monitor control unit			X		X
Side radar LH	X	X	X	X	X
Side radar RH	X	X	X	X	X
Drivetrain CAN communication unit
8CH CAN gateway	X	X	X	X	X
ECM	X	X	X	X	X
TCM		X	X	X	X
Engine CAN communication unit
ECM	X	X	X	X	X
Electric intake valve timing control module	X	X	X	X	X
IT CAN communication unit
8CH CAN gateway	X	X	X	X	X
AV control unit	X	X	X	X	X
TCU				X	X
Diagnostic CAN communication unit
8CH CAN gateway	X	X	X	X	X
Data link connector	X	X	X	X	X

×: Applicable

*1: With auto A/C

*2: With manual A/C

Nissan Sentra Vehicle EQUIPMENT IDENTIFICATION INFORMATION

Note:

Check CAN system type from the Nissan Sentra vehicle shape and equipment.

	Door mirror RH (side camera)		Telematics swich
	With Intelligent around view monitor system		With telematics system

Can Communication Signal Chart

CAN Communication Signal Chart

Refer to How to Use CAN Communication Signal Chart for how to use CAN communication signal chart.

Note:

Refer to Abbreviation List for the abbreviations of the connecting units.

T: Transmit R: Receive

Signal name	ECM	ABS	IPDM-E	TCM	8ch CGW	A-BAG	EPS/DAST 3	HFM	HVAC	M&A	BCM	SONAR	ICC 2	CCM	LASER	LANE	RDR-L	RDR-R	AV	AVM	A-AMP.	IVC	EVTC
Accelerator pedal position signal	T	R		R									R	R						R
A/C compressor request signal	T		R
Battery warning request signal (ECM)	T									R
Closed throttle position signal	T			R									R
Cooling fan speed request signal	T		R
Cranking enable (ECM) signal	T		R
ECM malfunction signal	T	R
ECO drive indicator control signal	T								R	R
ECO mode indicator signal	T^*1									R
ECO mode indicator signal										R	T^*2
ECO pedal guide signal	T									R
Electrical power cut freeze signal	T										R
Engine and CVT integrated control signal	T			R
Engine and CVT integrated control signal	R			T
Engine coolant temperature signal	T			R					R	R										R
Engine oil pressure warning lamp signal	T									R												R
Engine speed signal	T	R		R				R	R	R			R	R								R
Engine status signal	T	R	R				R			R	R									R		R
Engine warning display signal	T									R
Estimate drive torque signal	T													R
Fuel consumption monitor signal	T									R
Fuel filler cap warning display signal	T									R
ICC permission signal	T												R
ICC steering switch signal	T												R
Malfunction indicator lamp signal	T									R												R
Malfunction indicator lamp signal	R			T
Refrigerant pressure sensor signal	T								R
Remaining distance signal	T									R
Request drive torque signal	T													R
Request drive torque status signal	T													R
Stop/Start indicator lamp and message request signal	T									R												R
Stop/Start status signal	T			R
Stop lamp switch signal	T												R
		T												R
	R	R		R							T		R	R
Valve timing target position signal	T																						R
Nissan Sentra Vehicle speed display signal	T									R
Nissan Sentra Vehicle speed signal (ECM)	T					R
ABS malfunction signal	R	T		R									R
ABS operation signal	R	T		R									R	R
ABS warning lamp signal		T								R			R									R
Brake booster pressure status signal	R	T
Brake fluid pressure sensor signal	R	T
Brake fluid pressure signal		T											R	R
Brake warning lamp signal		T								R
Decel G sensor signal		T												R
ESS request signal		T									R
Front LH wheel speed signal		T												R						R
Front RH wheel speed signal		T												R						R
Odometer signal		T							R	R
Rear LH wheel speed signal		T												R						R
Rear RH wheel speed signal		T												R						R
Side G sensor signal		T											R	R
Start/Stop permit signal	R	T
	R		T
	R								T
	R			T
Steering angle sensor signal		T												R
													T		R
		R					R						R	T		R	R	R	R	R
Stop lamp request signal		T									R
Stop lamp request signal	R										R		T
TCS malfunction signal		T											R
TCS operation signal	R	T		R									R	R
VDC accept permission signal		T												R
VDC malfunction signal		T											R
VDC OFF indicator lamp signal		T								R
VDC OFF signal		T											R	R
VDC operation signal	R	T		R									R	R
VDC warning lamp signal		T								R												R
Nissan Sentra Vehicle speed signal	R	T	R	R			R	R	R		R	R		R					R
	R							R		T												R
													T		R	R	R	R		R
Nissan Sentra Vehicle speed signal (ABS)		T				R							R			R	R	R
Yaw rate signal		T											R
A/C compressor feedback signal			T						R
Battery warning request signal (IPDM E/R)			T							R
Front wiper stop position signal			T								R
Generator voltage request signal	R		T
Headlamp (Hi) ON signal	R		T
Headlamp (Lo) ON signal	R		T
Headlamp warning signal			T							R
Hood switch signal	R		T
Ignition switch ON signal			T					R			R			R
Ignition switch ON signal			R								T
Neutral position signal			T								R		R
Rear window defogger ON signal	R		T
Reverse position signal			T										R
Sleep-ready signal			T								R
								T			R
										T	R
											R								T
Starter control relay status signal	R		T								R
Starter relay status signal	R		T							R	R
Starter status signal	R		T
Cranking enable (TCM) signal			R	T
Current gear position signal				T									R	R
CVT accept permission signal				T										R
CVT fluid temperature signal	R			T
Drive sport mode indicator signal				T						R
ECO mode signal	R			T
G sensor signal	R			T
Input speed signal				T									R
N range signal		R		T
Output shaft revolution signal	R			T									R
P range signal		R		T
R range signal		R		T
Shift position indicator signal				T						R
Shift position signal	R	R		T						R	R	R	R				R	R	R	R
Transmission malfunction signal	R			T
Car crash information signal						T																R
Rear seat belt buckle switch (RH,CENTER and LH) signal						T				R
Seat belt buckle switch signal (passenger side)						T				R
Shock status signal						T					R
SRS air bag warning lamp signal						T				R
EPS operation signal	R						T
EPS torque on signal	R						T
EPS torque signal	R						T
EPS warning lamp signal							T			R
Buzzer output signal								T		R
										R	T
										R										T
Door lock/unlock request signal								T			R
Hazard request signal								T			R
Hazard warning lamp request signal								T			R
Ignition knob signal								T			R
Key warning signal								T		R
Lock warning signal								T		R
Panic alarm request signal								T			R
Push-button ignition switch status signal								T			R
A/C ON signal	R								T
Blower fan ON signal	R								T
Cooling fan request signal	R								T
ECV control signal			R						T
Rear window defogger request signal									T		R
Ambient temperature signal									R	T
Brake fluid level switch signal		R								T
ECO customize function signal									R	T
Fuel filler cap warning reset signal	R									T
Parking brake status signal	R									T
Parking brake switch signal		R								T
Remaining distance reset request signal	R									T
System selection signal										T		R	R			R	R	R		R
Nissan Sentra Vehicle speed signal (Meter)							R			T
VDC setting signal		R								T
Auto ACC status signal											T								R
Brake operation signal	R										T
Brake pedal position switch signal											T		R
Clutch pedal position signal			R								T
Daytime running light request signal			R								T
Delivery mode signal	R										T
Diagnosis mask status signal			R								T
Dimmer signal										R	T						R	R
Door lock status signal								R			T											R
Door switch signal	R							R		R	T									R		R
Driver seatbelt switch malfunction signal	R										T
Drive sport mode switch signal				R							T
Front fog light request signal			R								T									R
Front fog light status signal										R	T
Front wiper request signal			R								T									R
High beam request signal			R								T									R
High beam status signal										R	T
Ignition switch signal								R			T
I-key exist information signal	R										T
Illumination request signal											T								R
Light reminder warning signal										R	T
Low beam request signal			R								T									R
Low tire pressure warning lamp signal										R	T
Low tire pressure wheel location signal										R	T
Meter display signal										R	T
										R			T
										R				T
										R						T
										R							T
										R								T
										R										T
Passing request signal			R								T
Position light request signal			R								T									R
Position light status signal										R	T
Rear window defogger control signal	R										T
Rear window defogger feedback signal									R		T
Remote engine start status signal									R		T
Seatbelt buckle switch signal	R										T
Seat belt buckle switch signal (driver side)	R									R	T
Sleep wake up signal			R		R			R		R	T								R		R	R
Stop/Start OFF switch signal	R		R	R				R	R		T		R							R		R
TPMS malfunction warning lamp signal										R	T
Turn indicator signal		R	R							R	T		R			R	R	R		R
Parking sensor error signal										R		T
Rear object detection signal												T	R
Sonar indicator signal										R		T
Sonar sensor signal												T	R
AEB warning lamp signal										R			T
Brake fluid pressure control signal		R											T
Brake wheel torque signal		R											T	R
ICC operation signal	R												T
RAB warning lamp signal										R			T
Torque down request signal	R												T
Torque request signal	R												T
Wheel torque request signal	R												T
Active ride control signal		R								R				T
Drive mode status signal	R													T
Intelligent engine brake signal				R										T
Intelligent trace control signal		R												T
Steering angle sensor malfunction signal		R						R					R	T						R
Steering angle speed signal		R											R	T						R
Steering calibration signal		R												T						R
Distance sensor signal													R		T
Motor operation signal													R			T
Pedestrian ahead signal													R			T
Nissan Sentra Vehicle ahead signal													R			T
Driver assistance buzzer signal													R				T
Driver assistance buzzer signal													R					T
Auto ACC request signal											R								T
Camera switch signal																			T	R
View change signal																			R	T
Trouble detection signal	R																						T
Valve timing position signal	R																						T

*1: M/T models

*2: CVT models

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