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Audi A6 C5: How to Reprogram Key Fob

Has your key fob stopped working? Here's how to reprogram your key fob and gain back this convenient device.

By Gabriella Massari - March 30, 2016

This article applies to the Audi A6 C5 (1998-2004).

It gets knocked around on your key chain while you move around throughout the day and dropped to the bottom of your backpack or purse on a daily basis, but there's no mistaking how important your Audi key fob is. Because this device encounters daily wear and tear, it's no wonder you may need to reprogram it after a while. You won't need to see your local Audi dealer for help, though. You can program your key fob(s) right from the comfort of your Audi A6 C5.

Audi A6 C5 How to reprogram key fob infographic

Materials Needed

  • Two key fobs
  • An assistant/helper

We'll refer to one key fob as "Fob A" and the other as "Fob B" throughout this procedure.

Step 1 – Turn the car to "accessory mode" and follow locking sequence

  • Place "Fob B" in the ignition and turn it to "accessory mode."
  • Close the driver's side door and open the window.
  • Using "Fob A," press the "lock" button once. Then, press the "unlock" button. An alarm will beep and lights will flash, but door will remain locked.
  • Count to 10 seconds.
ACC mode
Figure 1. Put your car in "ACC" or "accessory" mode.

Step 2 – Use "Fob A" to unlock then lock door

  • Hand "Fob A" to an assistant or someone who can help from the outside of the car.
  • Using the key (not the fob buttons) on "Fob A," have your assistant unlock and then lock the door again.
  • Test "Fob A" by pressing the "unlock" button again. The door should unlock.
Figure 2. Hand "Fob A" to assistant outside of car.

Step 3 – Repeat the fob sequence

  • Open the door and turn the ignition fully off, and then back on again to "accessory mode" using "Fob A" this time.
  • Close and lock the door with "Fob B," leaving the ignition in "accessory on" mode.
  • Press "unlock" on the "Fob B" remote twice. The alarm will beep each time the button is pressed, but the door will remain locked.
  • Wait 10 seconds once more.

Step 4 – Complete the final test

  • Hand "Fob B" to your assistant, who will use it to unlock and lock the door again (using the key, not the fob buttons).
  • Test "Fob B" by pressing the "unlock" button again. The door should unlock.
  • Remove "Fob A" from the ignition, and perform a final test on both fobs by locking and unlocking the car, first with "Fob A" and lastly with "Fob B."

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