The NISSAN Vehicle Immobilizer System will not allow the engine to start without the use of a registered key.
If the engine fails to start using a registered key (for example, when interference is caused by another registered key, an automated toll road device or automatic payment device on the key ring), restart the engine using the following procedures:
1. Leave the ignition switch in the ON position for approximately 5 seconds.
2. Place the ignition switch in the OFF or LOCK position and wait approximately 10 seconds.
3. Repeat steps 1 and 2.
4. Restart the engine while holding the device (which may have caused the interference) separate from the registered key.
If the no start condition re-occurs, NISSAN recommends placing the registered key on a separate key ring to avoid interference from other devices.
Never leave these keys in the vehicle.
FCC Notice: For USA: This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.
NOTE:
Changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate the equipment.
For Canada: This device complies with Industry Canada license-exempt RSS standard(s). Operation is subject to the following two conditions: (1) this device may not cause interference, and (2) this device must accept any interference received, including interference that may cause undesired operation of the device.
Security indicator light

This light blinks when the ignition switch is placed in the LOCK position with the key removed from the ignition switch.
This function indicates the NISSAN Vehicle Immobilizer System is operational.
If the NISSAN Vehicle Immobilizer System is malfunctioning, the light will remain on while the ignition switch is placed in the ON position.
If the light still remains on and/or the engine will not start, seek service for the NISSAN Vehicle Immobilizer System as soon as possible. Please bring all registered keys that you have. It is recommended that you visit a NISSAN dealer for this service.
Vehicle security systemU1243 display unit
DTC Logic
Diagnosis Procedure
1.CHECK DISPLAY UNIT POWER SUPPLY AND GROUND CIRCUIT
Check display unit power supply and ground circuit
2.CHECK CONTINUITY OF COMMUNICATION CIRCUIT
Turn ignition switch OFF.
Disconnect display unit connector M142 and AV control unit
connector M163.
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B2191 difference of key
Description
Performs ID verification through BCM and Intelligent Key
when push-button ignition switch is pressed.
Prohibits the start of engine when an unregistered ID of Intelligent Key is
used.
DTC Logic
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PERFORM DTC CONFIRMATION PROCED ...
C1712 - C1715, C1720 - C1723, C1724 - C1727 transmitter malfunction
Description
One or more transmitters are malfunctioning internally.
DTC Logic
NOTE: The Signal Tech II Tool (J-50190) can be used
to perform the following functions. Refer to the Signal Tech II User Guide
for additional information.
Activate and display TPMS transmitter IDs
...