2003 FX45 - Just changed the battery in my Intelligent Key, after battery in one died and another dying.

Now the keyless function on the car door no longer works. Remote lock or unlock has both stopped working. The car still recognize the key, so I can keylessly start the car. Just need to use the actual key to open and clock doors.

If I hold down the unlock button, all the windows will roll down. If I hold the lock button, no reaction.

Can any of you recommend a way to resolve this? Your help much appreciated.