System Description

SYSTEM DIAGRAM 

Courtesy of NISSAN NORTH AMERICA, INC.

Component		Function
Door switch		Door switch detects door switch condition and then transmits door switch signal to BCM.
Stop lamp switch		Stop lamp switch detects that brake pedal is depressed, and then transmits stop lamp switch signal to BCM.
ABS actuator and electric unit (control unit)		ABS actuator and electric unit (control unit) transmits the vehicle speed signal to BCM via CAN communication.
TCM		TCM receives the P/N position signal from transmission range switch, and then transmits the shift position signal to BCM via CAN communication.
ECM		ECM controls the engine. When ignition switch is placed ON, Intelligent Key unit starts communication with ECM and performs the ID verification between Intelligent Key unit and ECM. If the verification result is OK, the engine can start. If the verification result is NG, the engine cannot start.
IPDM E/R		Starter cut relay is controlled by BCM, and starter relay is controlled by IPDM E/R while communicating with BCM.
BCM		When BCM receives a starter cut relay request signal from ECM, the starter cut relay is placed ON.
Ignition switch	Push switch	Ignition switch has push switch inside which detects that ignition switch is pressed, and then transmits the push switch signal to Intelligent Key unit. Intelligent Key unit changes the ignition switch position with the operation of ignition switch. Intelligent Key unit maintains the ignition switch position status while ignition switch is not operated.
	NATS antenna amp.	Refer to NATS Antenna Amp.
Intelligent Key		The Intelligent Key system is a system that makes it possible to lock and unlock the door locks (door lock/ unlock function) by carrying the Intelligent Key, which operates based on the results of electronic ID verification using two-way communication between the Intelligent Key and the vehicle (Intelligent Key unit).
Intelligent Key unit		Intelligent Key unit controls NISSAN VEHICLE IMMOBILIZER SYSTEM. Intelligent Key unit performs the ID verification between Intelligent Key unit and Intelligent Key when the Intelligent Key is carried into the detection area of inside key antenna, and ignition switch is pressed. If the ID verification result is OK, ignition switch operation is available. Then, when the ignition switch is placed ON, Intelligent Key unit performs ID verification between Intelligent Key unit and ECM. If the ID verification result is OK, ECM can start engine.

BCM INPUT/OUTPUT SIGNAL CHART 

Input Signal Item 

Transmit unit	Signal name
ECM	CAN communication	Engine status signal Starter cut relay request signal
IPDM E/R		Ignition ON signal Starter cut relay status signal Neutral position signal
ABS actuator and electric unit (control unit)		Vehicle speed signal
TCM		Shift position signal
Each door switch	Door switch signal
Stop lamp switch	Stop lamp switch signal

Output Signal Item 

Reception unit	Signal name
IPDM E/R	CAN communication	Ignition ON signal

INTELLIGENT KEY UNIT INPUT/OUTPUT SIGNAL CHART 

Input Signal Item 

Transmit unit	Signal name
IPDM E/R	CAN communication	Ignition ON signal
NATS antenna amp.	Key ID signal

Output Signal Item 

Reception unit	Signal name
IPDM E/R	CAN communication	Ignition ON signal
Inside key antenna	Key ID request signal

SYSTEM DESCRIPTION 

• The NISSAN VEHICLE IMMOBILIZER SYSTEM (NVIS) prevents the engine from being started by Intelligent Key whose ID is not registered to the vehicle (Intelligent Key unit). It has higher protection against auto theft involving the duplication of mechanical keys.
• The ignition key integrated in the Intelligent Key cannot start the engine. When the Intelligent Key battery is discharged, the NATS ID verification is performed between the transponder integrated with Intelligent Key and Intelligent Key unit via NATS antenna amp. when the Intelligent Key backside is contacted to ignition switch while brake pedal is depressed. If the verification result is OK, the engine start operation can be performed by the ignition switch operation.
• Up to 4 Intelligent Keys can be registered (including the standard ignition key) upon request from the owner.
• When replacing ECM, Intelligent Key unit or Intelligent Key, the specified procedure (Initialization and registration) using CONSULT is required.

PRECAUTIONS FOR KEY REGISTRATION 

The ID registration is a procedure that erases the current NATS ID once, and then registers a new ID. Therefore before starting the registration operation, collect all registered Intelligent Keys from the customer.

ENGINE START OPERATION WHEN INTELLIGENT KEY IS CONTACTED TO PUSH-BUTTON IGNITION SWITCH 

1. When brake pedal is depressed while selector lever is in the P position, Intelligent Key unit activates NATS antenna amp. that is located behind ignition switch.
2. When Intelligent Key (transponder built-in) backside is contacted to ignition switch, Intelligent Key unit starts NATS ID verification between Intelligent Key unit and Intelligent Key (transponder built-in) via NATS antenna amp.
3. When the ignition switch is placed to ON, Intelligent Key unit performs ID verification with the ECM. When the result is OK, engine start is permitted.
4. BCM detects that the selector lever position and brake pedal operation condition.
5. When ECM detects that the start engine conditions * are satisfied, it transmits a starter cut relay request signal to BCM.
6. When BCM receives a starter cut relay request signal from ECM, the starter cut relay is placed ON.
7. When starter cut relay is placed ON, IPDM E/R turns ON the starter relay and drives the starter motor.
8. When BCM receives an engine status signal from ECM, it turns the starter relay and starter cut relay OFF and stops cranking.

*: For the engine start condition, refer to "IGNITION SWITCH POSITION CHANGE TABLE BY PUSH-BUTTON IGNITION SWITCH OPERATION" below.

IGNITION SWITCH POSITION CHANGE TABLE BY PUSH-BUTTON IGNITION SWITCH OPERATION 

The ignition switch position can be changed by the following operations.

Vehicle speed: less than 4 km/h (2.5 MPH) 

Power supply position	Condition		Ignition switch operation frequency
	Selector lever	Brake pedal operation condition
OFF → ON	-	Not depressed	1
OFF → ON → OFF	-	Not depressed	2
OFF → STARTON → START	P or N position	Depressed	1
Engine is running → OFF	-	-	1

Vehicle speed: 4 km/h (2.5 MPH) or more 

Power supply position	Condition		Ignition switch operation frequency
	Selector lever	Brake pedal operation condition
Engine is running → OFF	-	-	Emergency stop operation
Engine stall return operation while driving	N position	Not depressed	1

Emergency stop operation

• Press and hold the ignition switch for 2 seconds or more.
• Press the ignition switch 3 times or more within 1.5 seconds.