Unable to unlock the ignition when key is in the ignition to start the car

Climb into the vehicle and close the door. Insert the key into the ignition but do not turn on the vehicle.
Hold down the "Unlock" button on the driver's door while turning the key to the right to the "Accessories" position. Continue holding down the "Unlock" button.
Turn the ignition key back to the "Off" position while continuing to hold the "Unlock" button then return the key to the "On" position again. Then return the ignition key to the "Off" position. As you complete this sequence, the doors will lock, and the horn will sound, indicating that you've entered the programming mode. At this point, release the "Unlock" button on the driver's door.
Push both the "Lock" and "Unlock" buttons on the key-less remote and hold them for roughly 15 seconds. Release the buttons when the locks click again.
Insert the key into the ignition and turn it to the "On" position. The horn will honk once more. This indicates the programming has been successful.
Remove the key from the ignition. Climb out of the vehicle and try locking and unlocking the doors with your remote key.
Tip

• The H3 uses a Tech ll code system that often cannot be re-programmed without the help of your local dealer. If you are unable to reset your key-less fob using the steps above, your local GM dealer will be able to help.

Often, you need to press the unlock button on the remote twice. First press unlocks the door and second press disables the immobiliser and allows the vehicle to start. The key alone will not start the vehicle.

Alternatively, when the key is in the ignition - press the remote unlock again.

The remote acts as an immobiliser device. The reason your car won't start on the key is probably because the system won't allow any key in the ignition - it is preventing theft of the vehicle. Once the unlock button on the remote is pressed the system then recognises that key is the legitimate one for the vehicle and the disables the immobiliser and allows you to start the car

Sounds as if the ignition cylinder has an internal problem. You may have a sticky wafer inside the cylinder. You can try using some WD 40 and inserting the straw inside the cylinder and giving it a good spray. You can also try gently rocking the steering wheel back and forth while trying to turn the key. With out the ignition cylinder turning, the gearshift will not come out of park nor will the steering wheel come unlocked. Hop this helps

try locking and unlocking drivers door lock with the key

hi well this is a bit long so if you can bare with me i will try explain how to , clear system to decode, and recode as this is what it sounds like that the coding has gone from the ignition key....ok here goe's
to sync key with car depress lock or unlock button manually lock the drivers door within 30 seconds of the above system should now work....if not do next bit
switch ignition on ( using non chip key ) manually lock drivers door using key ( another one, hopefully you will have more than one) press unlock button 5 times, in one second intervals indicators flash 5x for every time signal is received switch ignition off and remove key
that's the de-programming done...
to de-program the system if above fails..........
switch ignition on ( use key without remote ) manually lock drivers door using key to be synced with car complete the following within 30 seconds of doing above within 5 seconds press the unlock button on key indicators should flash once wait 5 seconds press unlock button once to confirm programming vehicle should unlock this also will confirm deactivation of programming mode switch ignition off remove key..that should be it, then try new programed key in ignition.

to re-program system and sync with key switch ignition on manually lock drivers door using key ( another one, hopefully you will have more than one) press unlock button 5 times, in one second intervals indicators flash 5x for every time signal is received switch ignition off and remove key
that should be it, if no joy then will have to main dealer i am afraid...hope this helps

Did you park on a hill or in a tight parking spot with your steering wheel cranked to one side?
Try turning the steering wheel (will be very hard to do) as you put the key in the ignition and try to turn the key on, if that doesn't work, try turning the wheel the other way while turning on the key.

try wiggleling the key too the tumblers may be getting worn in the ignition is this works then replace the ignition

I am having same trouble with 2006 Murano. Ignition will not turn electronically. Manual key won't turn either.

See Procedure for REPLACEMENT.

1. Disconnect the negative (-) battery terminal. 2. Remove the crash pad side cover (A). 3. Remove the ignition switch (A) after loosening the screw and disconnecting the 6P connector. 4. Remove the steering column shaft (Refer to the ST group). 5. Remove the key warning switch and key illumination lamp (A) after loosening the screws and disconnecting the 6P connector. 6. If it is necessary to remove the key lock cylinder (A), Remove the key lock cylinder (A) after pushing lock pin (B) with key ON. 7. Installation is the reverse of removal procedure

In answer to your question nothing had been replaced or repaired prior to the problem.
Batteries in all the remotes or the car have been renewed. Problem still exists.
Removal and replacement of the fuse 25 resetting the ignition module. Starting the engine and moving the car to a different location the locking system operated normally but on returning to my home the system failed.
My wife returned home later and her car a different make and model would not lock.
I have since turned off my broadband wireless network system and holding the lock button for approx 15 seconds the lock operated.
I will post findings after further trails