Please do not call us on the phone about sidewinder keys. Send us an email with your vin and if possible an image of your key blade. We really cannot stop what we are doing and answer questions on the phone without that information first. You will receive a reply with prices, and instructions according to your specific car.

Sidewinder Audi key application 1997 to 2005

This guide will be updated as information and applications are verified. Audi does not
have a comprehensive application guide or chart. Nor is their parts application of these remotes complete or specific.

Please understand any remote for that year group of Audi can be matched to any Audi in the same group.
This is called matching the remote to the car. This is the 2 key procedure and has nothing to do with the key itself.
One remote can be matched to any number of Audis that it is designed to work for. It transmits a digital signal. You teach the car to respond to that unique signal. Have a Audi TT and a Audi A6 ? it can open doors on all of them, and if the cars are close together, it can lock and unlock all of them at the same time.
Keys are activated. The car sends a pulse through a coil of wire located around the ignition switch. The chip in the key is excited. If the chip has been imprinted with the identity of that car it will see its reflection and allow the motor to run on most 2002 and newer Audis.
Keys previously activated to a different car cannot be imprinted with a new identity. (write only) so used keys will not work on another Audi. Only the remote portion can be used with another Audi.

Most often miss understood is programming. Programming the button REMOTE portion of the key is simple and referred to as matching.
You may need 2 keys. You must be able to lock the drivers door and have the red led alarm light next to the lock button blink. If it does not blink, the alarm does not know the door is closed and will not go into matching mode.
The NAA keys are cut by using your serial number to the car (vin dependent) There is a 4 digit key code, unless you are the original owner or you have the black zip tie tag that was attached to the black valet key, you will not have the key code. We use an image of your key to verify the code to be cut.

Applications contained here-in are for the Audi models in North America. Audi has 7 markets worldwide. Due to frequency licensing in different countries the remotes will have other part numbers similar to ones here in the USA.

Here is the short version:

2002-2005 Audi TT: any HAA key works, 3 button remote = 4D0837231N , immobilizer system

2001 to 2002 Audi A6: any HAA Key works, 3 button remote 4D0837231P immobilizer system

note: decimal point refers to month of manufacture 2006.3 means March, 2005.6 means June

Audi security key system is like the old VW bug with the cart in front of the horse, you program the car to the key, not the key to the car.

Starting in 1998 with the Audi TT, A4 A6 the key does not have a computer chip, and does not need to be activated. The remote has the oval 3 button HLO 4D0837231Q (2 button T) . The remote has a swivel loop to attach to a key ring. This remote will not work with A6 Quattro and newer Audi . Some models, the transition date is different, look for the yellow car with the key under it when you turn the ignition on. See the yellow car? It only comes on for a few seconds when you turn the ignition on. Using a key not coded to the car will cause the light to blink and the engine will shut off

Audi A4 through 2001 and the S4 through 2002 do not have Immo at all. These are B5.

A4 (B6) starting 2002 through 2005.5 have Immo3.

A4 (B7) starting 2005.5 have Immo3. I do not know if they changed and went to Immo4 (Fazit) during this run.

A6 (C5) from 1998 through 2000 have no Immo.

A6 (C5) 2001 through 2005 have Immo3 although the first 2001 cars off the line in about May/June 2000 did not get it installed.

I'm not that familiar with the TT from that timeframe but I think it's similar to the A6 -- Immo3 starting 2001..

I have done a ton of searching and found how to accurately program a key fob on the forums. The problem with all the directions that I had found was that once I programmed one key fob, the others would erase.

None of the directions showed all the steps to program more than one key correctly without losing the others (which most people will have). This DIY has the correct programing procedure no matter how many fobs you have.

For some reason if you pull your battery or you change the battery in your fob you might be finding a situation where you need to do this programming.

There are two kinds of programming. If you have remotes that have been programmed to the car previously the steps are easy. There are longer steps if the keys are new and those are the secondary ones.

Steps to reprogram keys to a car they are already linked to:
1. Press and hold the unlock key on a remote
2. Insert key in ignition and turn to on (while still holding unlock)
3. Hold unlock while in the on position for 2 seconds
4. Turn key to off, remove from ignition and release button.

Do this for each remote. Relink to seat positions (press and hold mem position #, then unlock button for 2 seconds and release both) and done.

To program new remotes on a car never linked to previously:

1. Take a key (valet key works best, put it into the ignition and turn the key to the "on" position, so the dashboard lights come on.
2. Roll down the driver's side window (not required, but a good idea in case there's a problem).
3. Exit the car and close the door.
4. With a second key, physically lock the doors by turning the key clockwise (don't use a remote).
5. Take the first remote to be programmed, press the unlock button. The lights will flash once.
6. Wait 10 seconds and press the unlock button. The doors should unlock. That first transmitter is now programmed.

***If you have only one key skip to step 16. Otherwise continue to step 7.***

7. Lock the door again (physically) with the key, (not the remote) by turning clockwise.
8. Press the unlock button two times with a one second interval in between, the lights will flash with each button press for a total of two flashes.
9. Wait 10 seconds and press the unlock button. The doors should unlock. The second transmitter is now programmed.

***If you have three keys proceed to step 10. Otherwise skip to step 16.***

10. Lock the door again (physically) with the key, (not the remote) by turning clockwise.
11. Press the unlock button three times with a one second interval in between, the lights will flash with each button press for a total of three flashes.
12. Wait 10 seconds and press the unlock button. The doors should unlock. The third transmitter is now programmed.

***If you have four keys proceed to step 13. Otherwise skip to step 16.***

13. Lock the door again (physically) with the key, (not the remote) by turning clockwise.
14. Press the unlock button four times with a one second interval in between, the lights will flash with each button press for a total of four flashes.
15. Wait 10 seconds and press the unlock button. The doors should unlock. The fourth transmitter is now programmed.

16. Remove the key from the ignition.

Make sure that to test the newly program remotes, the original key is removed from the ignition since this exits the programming process. Someone might be a bit frustrated trying to test it with it still in 'program' mode.

I had some diffuculty accessing the programming mode. If it doesnt work then take the key out of the ignition and start over. Rinse lather repeat. It will go eventually.

If you are still having problems after trying it more times than you can count, check the key is right one for year of car or that the key and battery are good.