I want added second ignition key for my vehicle.

Did you have the new PCM / ECM programmed to the vehicle , anti-theft key programmed to the vehicle ? P1631 Immobilizer fuel enable signal not correct ? need key programmed .Your best bet,take it to a qualified repair shop. You have no idea what your dealing with .

The Immobilizer needs to be reset to the vehicle so the ECM and BCM recognize it.

https://www.google.com/search?q=2006+honda+odyssey+reset+immobilizer

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It's anti-theft security system, Nissan Vehicle Immobiliser System (NVIS)

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 placed 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.

Statement related to Section 15 of FCC Rules for NISSAN Vehicle Immobilizer System (CONT ASSY - IMMOBILIZER, ANT ASSY - IMMOBILIZER) This device complies with part 15 of the FCC Rules and RSS-210 of Industry Canada. 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 of the device.

CHANGES OR MODIFICATIONS NOT EXPRESSLY APPROVED BY THE PARTY RESPONSIBLE FOR COMPLIANCE COULD VOID THE USER'S AUTHORITY TO OPERATE THE EQUIPMENT.




Security indicator light

For vehicles without Intelligent Key: This light blinks whenever the ignition switch is placed in the LOCK, OFF or ACC position.

For vehicles with Intelligent Key: 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, see a NISSAN dealer for NISSAN Vehicle Immobilizer System service as soon as possible. Please bring all registered keys that you have when visiting your NISSAN dealer for service.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

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Programming
When
Remote control added or replaced. System malfunction.
How
Obtain all remote controls. A maximum of 3 remote controls can be programmed. Switch ignition ON. Repeat procedure below 3 times: Within 4 seconds: Press lock or unlock button. Within 4 seconds: Switch ignition OFF. Within 4 seconds: Switch ignition ON. Within 4 seconds: Press lock or unlock button. System should now lock or unlock vehicle. Within 4 seconds: Press lock or unlock button. Within 10 seconds: Press lock or unlock button of first remote control. System should now lock or unlock vehicle. Press lock or unlock button of second remote control. System should now lock or unlock vehicle. Press lock or unlock button of third remote control. System should now lock or unlock vehicle. Switch ignition OFF. Remove key. Check operation of all programmed remote controls.
IMMOBILIZER CAN ONLY BE SET BY DIAGNOSTIC EQUIPMENT

When the ignition switch is turned on, the immobilizer control module sends a challenge signal through the antenna around the ignition switch to the transponder chip in the ignition key. The transponder key responds with an encrypted key code. The immobilizer module then decodes the key code and compares it to the list of registered keys. When the engine is started, the ECM sends a request to the immobilizer module over the data bus to verify the key is correct. If an attempt is made to start the vehicle with an invalid ignition key, the immobilizer module sends a message over the data bus to the instrument cluster to flash the anti-theft indicator lamp. If the ECM does not receive a "valid key" message from the immobilizer module within 2 seconds of engine start up, the ECM will disable the fuel injectors to kill the engine. You'll need to get a new key and get it registered in the immobilizer control module. You'll need a scan tool, the VIN number, the date manufactured and a factory-assigned PIN number.

PUT THE RIGHT KEY IN THE IGNITION SWITCH TURN IGNITION SWITCH TO ON POSITION UNTIL IMMOBILIZER WARNING LAMP ILLUMINATES FOR FEW SECONDS.KEY HAS RESET.IF IMMOBILIZER WARNING LAMP FLASHES RAPIDLY KEY DID NOT RESET.TRY TURN SWITCH ON WITH KEY UNTIL IMMOBILIZER LIGHT ILLUMINATES FEW SECONDS TURN OFF YOU READY TO GO GO GO.IF CANT RESET HONDA DEALERSHIP HAS TO USE DIAGNOSTIC EQUIPMENT TO RESET KEYS TO IMMOBILIZER MODULE.

Programming
When
Remote control added or replaced. System malfunction.
How
Obtain all remote controls. A maximum of 3 remote controls can be programmed. Switch ignition ON. Repeat procedure below 3 times: Within 4 seconds: Press lock or unlock button. Within 4 seconds: Switch ignition OFF. Within 4 seconds: Switch ignition ON. Within 4 seconds: Press lock or unlock button. System should now lock or unlock vehicle. Within 8 seconds: Press lock or unlock button of first remote control. System should now lock or unlock vehicle. Press lock or unlock button of second remote control. System should now lock or unlock vehicle. Press lock or unlock button of third remote control. System should now lock or unlock vehicle. Switch ignition OFF. Remove key. Check operation of all programmed remote controls.
NOTE: If less than 3 remote controls are to be programmed, remove ignition key after programming last remote control
NOTE THIS IS FOR YEAR 99-02

That's your immobilizer system light:
The Immobilizer System protects your car from theft. A properly coded master or valet key must be used in the ignition switch for the engine to start.
If an improperly coded key (or other device) is used, the engine’s fuel system is disabled.
When you turn the ignition switch to ON (II), the Immobilizer System indicator should come on for a few seconds, then go out. If the indicator starts to blink, it means the system does not recognize the coding of the key. Turn the ignition switch to LOCK (0), remove the key, reinsert it, and turn the switch to ON (II) again.
The system may not recognize your key’s coding if another immobilizer key or other metal object is near the ignition switch when you insert the key. To make sure the system recognizes the key code:
Do not keep other immobilizer keys on the same key ring.
Use a plastic or leather key fob, not metal.
Keep other keys away from your vehicle’s key and the ignition switch while trying to start the engine.
Do not attempt to alter this system or add other devices to it. Electrical problems could result that may make your car undriveable.
This indicator will also blink several times when you turn the ignition switch from ON (II) to ACCESSORY (I) or LOCK (0).
If the system repeatedly does not recognize the coding of your key, contact your Honda dealer.
If you have lost your key and you cannot start the engine, contact your Honda dealer.
Hope this lets you understand the light, and what should be happening.