Nissan Sentra. Manual - part 778

SEC-140

< SYSTEM DESCRIPTION >

[WITHOUT INTELLIGENT KEY SYSTEM]

COMPONENT PARTS

Key switch

Input key switch ON/OFF condition to BCM.

Horn

Provides audible warning in panic mode.

Item

Function

SYSTEM

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SYSTEM

NISSAN VEHICLE IMMOBILIZER SYSTEM-NATS
NISSAN VEHICLE IMMOBILIZER SYSTEM-NATS : System Diagram

INFOID:0000000009756797

NISSAN VEHICLE IMMOBILIZER SYSTEM-NATS : System Description

INFOID:0000000009756798

INPUT/OUTPUT SIGNAL CHART

BCM

SYSTEM DESCRIPTION

NATS (Nissan Anti-Theft System) has the following immobilizer functions:

• Engine immobilizer shows high anti-theft performance to prevent engine from starting by anyone other than

the owner.

• Only a key with key ID registered in BCM and ECM can start engine, and shows high anti-theft performance

to prevent key from being copied or stolen.

• Security indicator always flashes with mechanical key removed condition (key switch: OFF) 

• Therefore, NATS warns outsiders that the vehicle is equipped with the anti-theft system.

• If system detects malfunction, security indicator illuminates when ignition switch is turned to ON position.

• If the owner requires, ignition key ID or mechanical key ID can be registered for up to 5 keys.

• During trouble diagnosis or when the following parts have been replaced, and if ignition key is added, regis-

tration

*1

 is required. 

*1

: All keys kept by the owner of the vehicle should be registered with mechanical key.

- ECM

- BCM

- Ignition key

- Remote keyless entry receiver

• NATS trouble diagnosis, system initialization and additional registration of other mechanical key IDs must be

carried out using CONSULT.

• When NATS initialization has been completed, the ID of the inserted mechanical key or mechanical key IDs

can be carried out.

• Possible symptom of NATS malfunction is “Engine cannot start”. Identify the possible causes according to

“Work Flow”, Refer to 

SEC-171, "Work Flow"

.

• If ECM other than Genuine NISSAN is installed, the engine cannot be started. For ECM replacement proce-

dure, refer to 

EC-485, "Removal and Installation"

.

PRECAUTIONS FOR KEY REGISTRATION

ALKIA2974GB

Switch/Input signal

Input signal to BCM

BCM function

Actuator/Output signal

NATS antenna amp.

Key ID

NATS

• Security indicator lamp
• Starter request

ECM

Engine status signal

SEC-142

< SYSTEM DESCRIPTION >

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SYSTEM

• The key registration is a procedure that erases the current NATS ID once, and then re-registers a new ID.

Therefore the registered key is necessary for this procedure. Before starting the registration procedure, col-

lect all registered Keys from the customer.

• The NATS ID registration is the procedure that registers the ID stored into the transponder (integrated in

mechanical key) to BCM.

The key ID registration is the procedure that registers the ID to the BCM.

• When performing the key system registration only, the engine cannot be started by inserting the key into the

key cylinder. When performing the NATS registration only, the engine cannot be started by using the ignition

key.

SECURITY INDICATOR

• Always flashes with ignition key in the OFF position. 

MAINTENANCE INFORMATION

CAUTION:

It is necessary to perform NATS ID registration when replacing any of the following parts.

If ID registration is mot performed the electrical system may not operate properly.

• BCM

• ECM

• IPDM E/R

• Ignition key

• NATS antenna amp.

• Dongle unit (Canada only)

• Combination meter

VEHICLE SECURITY SYSTEM
VEHICLE SECURITY SYSTEM : System Diagram

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VEHICLE SECURITY SYSTEM : System Description

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• The vehicle security system has two alarm functions (theft warning alarm and panic alarm), and reduces the

possibility of a theft or mischief by activating horns and headlamps intermittently.

• The panic alarm does not start when the theft warning alarm is activating, and the panic alarm stops when

the theft warning alarm is activated.

ALKIA2985GB

SYSTEM

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The priority of the functions are as per the following.

THEFT WARNING ALARM

• The theft warning alarm function activates horns and headlamps intermittently when BCM detects that any

door is opened by unauthorized means, while the system is in the ARMED state.

• Security indicator lamp on combination meter always blinks when ignition switch is in any position other than

ON. Security indicator lamp blinking warns that the vehicle is equipped with a vehicle security system.

Operation Flow

Priority

Function

1

Theft warning alarm

2

Panic alarm

JMKIA5416GB

No.

System state

Switching condition

1

DISARMED to 
PRE-ARMED

When all conditions of A and 
one condition of B is satis-
fied.

A

B

• Ignition switch: OFF
• All doors: Closed

All doors are locked by:
• Door key cylinder LOCK switch
• LOCK button of Keyfob
• Door lock and unlock switch

2

PRE-ARMED 
to ARMED

When all of the following 
conditions are satisfied for 
30 seconds.

• Ignition switch: OFF
• All doors: Locked

3

ARMED  to 
ALARM

When all conditions of A and 
B are satisfied.

A

B

Keyfob: Not used

• Any door: Open

4

DISARMED to 
PRE-RESET

No conditions.

5

PRE-ARMED 
to PRE-RESET

6

ARMED  to 
PRE-RESET

7

ALARM to 
PRE-RESET

8

PRE-RESET to 
DISARMED

9

PRE-RESET to 
PRE-ARMED

10

PRE-ARMED 
to DISARMED

When one of the following 
condition is satisfied.

• Ignition switch: ACC/ON
• Door key cylinder UNLOCK switch: ON
• UNLOCK button of Keyfob: ON
• UNLOCK switch of door lock and unlock switch: ON
• Any door: Open