Also, try this method if above one doesn't work
You will need BOTH remote key fobs to reprogram one or both of them.
1. Take the key you DO NOT want to reprogram and put it in the ignition.
2. Turn the ignition on but DO NOT start the engine.
3. Put the second key in the drivers door lock. Whilst it is in the lock press the UNLOCK button once only (the lights should flash on the car but the doors will remain locked).
4. With the second key still in the drivers door lock, unlock and then lock the door again.
5. Remove the key from the door lock.
6. Open the car and remove the key from the ignition.
7. Now test the key that you have reprogrammed, the one you have removed from the door lock.
If both your remotes don't work, do all of the above for the first key, but at step number 3. press the UNLOCK button TWICE. The light will flash twice and then proceed onto step 4 and finish the procedure.