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Audi: What's Wrong with My Key Fob?

Has the key fob to your Audi stopped working? Keep reading because we've got the most likely culprits.

By Charlie Gaston - April 5, 2016

This article applies to the Audi A3, A4, A6, Q5, and Q7.

When it comes to hardware devices, we have to be honest and say the key fob ranks pretty high on the list for being the most convenient one out there (automotive or otherwise). Just a few inches in length, this handy device can really change the way you move about your day. Not only does it allow you to quickly and easily enter and exit your Audi with ease, but it's also very easy to troubleshoot. Often times, you won't need to make a service appointment at your local Audi dealership for professional assistance. You can simply do the repair right from the interior cabin of your car. Let's get started on the must-know information you'll need to troubleshoot and fix your Audi key fob.

Materials Needed

  • Replacement fob battery
  • Flathead screwdriver
  • Ross-Tech software
  • VAG-COM
  • Laptop
  • Valet key
  • Volt meter
  • OBD-II tool

Step 1 – Check the fob battery

It might be dead.

It's easy to overlook, but this crucial step could save you time and money. To check your key fob battery, simply remove the cover to your key fob. Remove the battery by hand or by using a small flat head screwdriver. If your battery is fine, and you just purchased your key fob, have your local Audi dealer check to see if your key fob has been matched to your engine immobilizer. If you own the Ross-Tech software, and are comfortable completing the matching procedure, go ahead and match your key fob to your immobilizer-equipped Audi on your own. You will need your vehicle identification number (VIN) before getting started.

  • VAG-COM will validate the programming information you enter into your car's computer via your instrument cluster and laptop.
  • You will also need your valet key and a volt meter to measure how much voltage is left in your battery.
  • The full instructions for matching your key fob to your immobilizer-equipped Audi are listed in the Related Discussions section below.
Figure 1. Audi key fob disassembly.

Pro Tip

While you are replacing the battery to key fob, go ahead and check to see if any of the interior pins are bent, as this could cause the key fob to stop working. If you feel comfortable doing so, try to make good positive contact between the pins, taking time to unbend them as needed.

Step 2 – Reprogram the key fob

The programming might have become lost over time.

This is a simple do-it-yourself task that you can complete in under 15 minutes. Here's how:

  • From inside your car, go ahead and press the "unlock" button on your key fob.
  • Next, put your key in the ignition, and then turn it to the "ACC on" position.
  • Immediately after, turn your key to the "off" position.
  • Remove your key, and then press the "unlock" button one last time.
Figure 2. You won't need to visit a local Audi dealer to reprogram your key fob.

Step 3 – Run your trouble codes

There might be a larger issue at play.

Depending on whether or not you own an on-board diagnostic tool, now is the time to go ahead and run your trouble codes. If you don't own an on-board diagnostic tool, your local Audi dealer can run your codes for you.

  • If you can't run diagnostics on your car, and cannot afford to pay a local Audi dealer to do so for you, you have one final option.
  • Disconnect your car battery, starting with the negative terminal first.
  • Wait at least 30 minutes before reconnecting your car battery, and then re-program your key fob, as needed.
Figure 3. Your diagnostic trouble codes could reveal key information about your car's locking system.

Related Discussions and Site