Reprogramming Key Fob after Battery Replacement.
Replacement Battery
CR2032 is what you need. 
Please find below a number of alternatives to solve more than one challenge.
Most of the solutions below do not Re-program the Fob - they simply pair, synchronize or re-fresh the code stored in the Fob.
- Replaced batteries and Fob does not work. (when you have TWO Fobs - Remotes)
1 - Two Fobs - New Batteries.
- Step - Insert one key into the ignition and turn on.
- Step - Close the door, lock the door with the key hole on driver door ,with the key you want to program.
- Once the door is locked take the key out of the door and press the open button once or 2 or 3 or 4 times depending on which key is being reprogrammed (for the seats memory). You will see the side indicator blink every time you press the button, wait 6 secs and press the OPEN button again once.
- Open the door and switch off the ignition, take the key in the ignition out.
- Close the door and try locking with the reprogrammed key.
if you lost the program on other key it's just you didn't select the right seat memory, so set the right seat number for the right key
For Example :My wife is 1# in the seat memory, mine is 2#.
So i needed to press the open button twice in step 3.
There's a procedure in the manual for this, page 61. Well, it's not exactly reprogramming, it's more like re-Synchronizing. Due to the rolling code mechanism, if you press a button too many times while you're out of range, you lose sync with the vehicle. To reset this, they advise a 2-step procedure.
1. Press either LOCK or UNLOCK on the keyfob *one* time only.
2. Within 60 secs, use the key to manually lock or unlock the driver's door.
The keyfob should work again. (I've done it after my fob no longer worked after battery replacement, it works.)
On the multi-key programming procedure above, it DOES work, so thanks! Interesting note: the key that's *in the ignition* for that procedure does NOT need to have a valid immobilizer transponder chip; the car apparently doesn't check for that before allowing additional fobs to be registered. Also, the procedure worked even when *none* of my fobs were workable, even after trying the page 61 procedure spelled out above.
So, once again, Thanks!
1. Press either LOCK or UNLOCK on the keyfob *one* time only.
2. Within 60 secs, use the key to manually lock or unlock the driver's door.
The keyfob should work again. (I've done it after my fob no longer worked after battery replacement, it works.)
On the multi-key programming procedure above, it DOES work, so thanks! Interesting note: the key that's *in the ignition* for that procedure does NOT need to have a valid immobilizer transponder chip; the car apparently doesn't check for that before allowing additional fobs to be registered. Also, the procedure worked even when *none* of my fobs were workable, even after trying the page 61 procedure spelled out above.
So, once again, Thanks!
ONE FOB - REPROGRAM
Yes, you can reprogram an fob with a single key...don't exactly know how...but read on:
I had researched the same thing after purchasing a new fob cover. The remote would not work and, as you can guess, I found out about the programming after the fact. I too only have a single key that came with the car when I bought it a week ago.
I went out to the car, put the key in the drivers side door, turned it like I was unlocking it, pushed the unlock/lock buttons ... ...and the lock clicked...the remote worked fine after that.
Good Luck...at least there is hope :-)
2004 All-road.
This procedure worked for me...but not exactly as described.
Two fobs - I lost the sync on both of them.
My fob is seat position 1. Wife's fob is seat position 2.
1) I put the wife's key in the ignition and turned it on.
2) I used my key to manually lock the car.
3) I pushed the unlock button once. The side marker lights blinked.
4) Waited a bit and pushed the unlock button again. Nothing happened.
5) Unlocked the car manually.
6) Removed wife's key from the ignition.
7) Tested my fob - it worked exactly as it should (seat moves to position 1)
8) Put my key in the ignition and turned it on.
9) Locked the car manually with my wife's key.
10) Pushed the unlock button once - side markers blink.
11) Pushed the unlock button again right away - nothing happened.
12) Scratched my head a bit and pushed the unlock button a third time - still nothing.
13) Unlocked the door manually with my wife's key and removed my key from the ignition.
14) Tested the wife's fob and it worked exactly as it should (seat moves to position 2)
So either the fobs remembered their seat programs, or I inadvertently did the right sequence....but either way I did not get a lights flashing signal when I pushed the unlock button on my wife's fob the second time.
Thanks to the OP for posting this. Saved me a pain in the *** trip to the dealer. That's all my manual tells me to do.
13) Unlocked the door manually with my wife's key and removed my key from the ignition.
14) Tested the wife's fob and it worked exactly as it should (seat moves to position 2)
So either the fobs remembered their seat programs, or I inadvertently did the right sequence....but either way I did not get a lights flashing signal when I pushed the unlock button on my wife's fob the second time.
Thanks to the OP for posting this. Saved me a pain in the *** trip to the dealer. That's all my manual tells me to do.
2004 B6
car battery died.charged it.
remote no talky after.
GRRRR.
as posted previously above, and thank you VERY much for it, this worked for me:
1 - put driver window down.
2 - insert key in door lock
3 - twist to unlock and hold in position.
4 - with other paw unlock the car using the door panel button.
5 - release and remove key from door.
6 - test remote.
A4 Quattro
I used the following method and it restored my primary key but not my secondary key. I tried 6 times no success, tried another method still no luck. So now I have discovered another method that worked for me
I put the key I want to program in the ignition and turned it on, leaving it in the ignition and ON I pushed the lock button on the fob. Then hey presto I pressed it again and it worked! Hope this helps someone else, I have an A4 Quattro.
I put the key I want to program in the ignition and turned it on, leaving it in the ignition and ON I pushed the lock button on the fob. Then hey presto I pressed it again and it worked! Hope this helps someone else, I have an A4 Quattro.
I had 2 fobs one that I had not used in three years, I looked on the forum and all other methods failed. I came across one that instructed me to insert the key in question into the ignition, turn it on whilst still in the ignition and in the on position I pressed the unlock button and this worked. This guys is a star, it worked for me. This is the only method that worked for me after all other options failed, you are a star.
Audi A4 2006.
On some models you don't even need second key. Few minutes ago I just re linked my key by just switching on ignition, then pressed unlock button four times and after waiting 3-5 seconds pressed it once again and voila - my key is linked back.
Audi A4 2006.
Audi A4 2006.