Before you begin pairing your New Jawbone with your mobile phone, make sure you have activated your phone's Bluetooth function. Also, ensure that your phone and New Jawbone are within one yard (3 feet) of each other.
When you turn on your New Jawbone for the first time (by pressing and holding the Talk Button for 3 seconds), the LED light should flash red and white alternately. This means it's in Pairing Mode. You can now search for the Bluetooth device from your phone.
(If this is not the first time the Jawbone is being paired, turn off the New Jawbone. Then, hold down the NoiseAssassin™ button and the Talk button at the same time for 3 seconds until the LED indicator light flashes red and white alternately. This will put the Jawbone into Pairing Mode.)

Once you have set your phone to search for Bluetooth devices and your phone detects the New Jawbone, you have to "add" the device to your phone. Consult your phone's instruction manual for this process. (Note: A common issue occurs when a user tries to pair the Jawbone without "adding" the headset as a Trusted device to the phone, having only made their phone discoverable.)
It's at this point you should be prompted for the Pass Key. Enter 0000. Be certain to enter zeroes and not the letter "O".
Another thing you may want to try is resetting and re-pairing your New Jawbone. If this does not resolve the issue, you may want to perform a soft reset on your phone. Please consult your phone owner's manual for instructions regarding how to perform a soft reset. Generally, this is a secure process. You should not lose any information that you have stored on your phone. However, it is always a good practice to back up your information in the event you inadvertently delete any contact information, photos, ringtones, etc.
(Note: You may need to re-pair your New Jawbone after you perform a soft reset on your phone.)