I changed the battery on the master key. It's working now. I'll do the same with the spare key
In case the key fob loses sync with the car, this is what you do:
1. Sit in the car with all doors/bootlid tightly closed
2. Turn the key to the ON position, marked by "II" on the ignition bezel so the dash lights come on, then within 5 seconds press the "Lock" button on the remote for 1 second or so and release the button.
3. Turn the key to the OFF position, marked by "I" on the ignition bezel - dash lights go off.
4. Repeat steps 2 & 3 three more times (A total of 4 times) - each step must be done within 5 seconds of the previous step.
5. Upon the 4th turning of the key to "ON", press the lock button on one remote, the locks will make a cycling sound (clunk), locks will NOT lock or unlock at this point, they will just make a noise. The system is now in programming mode. Do not turn key off.
6. Within 5 seconds of entering programming mode and within 5 seconds of each other, press the lock button ON EACH remote you are programming, for a second or so and release. This step needs to be completed within 10 seconds. Each time a remote button is pushed, the locks should cycle. Up to 3 remotes can be programmed.
7. Turn ignition completely off and remove the key. Step out of car and close door. The remotes should be programmed and should work. If you have a bootlid/hatch release, the button for this feature needs to be held for a few seconds before the bootlid/hatch will "pop".