You press the button on your key, but the car won't unlock first time. You have to get right up close, or a message pops up on the dashboard saying "Replace key battery". Chances are, the battery is on its way out. Changing it is easy enough, but I've seen people break perfectly good keys just trying to replace a battery. That's why I want you to be careful. If you're doing an Audi key battery replacement yourself, here's what you need to know.
How can you tell when your key battery is running low?
- The car only unlocks when you're standing right next to it.
- You have to press the button several times before the car responds.
- With keyless entry, the car doesn't detect the key and asks you to hold it against a specific spot.
- A warning appears on the dashboard telling you the key battery is low.
How do you replace the Audi key battery yourself?
- Remove the mechanical key from the fob. There's usually a small button or sliding catch.
- Carefully open the battery cover using a plastic tool or a coin. Don't force the plastic clips.
- Look at how the old battery sits inside and remember which side faces upwards.
- Fit a new battery of exactly the same type. Just be careful not to touch the contacts with your fingers.
- Close the cover and check that the buttons work.
Do you need to reprogramme the key after changing the battery?
With most Audi and VW keys, there's no need to reprogramme anything. You pop in the new battery and the key works as normal. If nothing happens, first check that you've fitted the battery the right way round and that the new battery isn't flat. If everything looks fine but the key still won't respond, bring it in and we'll have a look. Sometimes it simply needs resynchronising with the car.
Please, don't try to prise the key open with a screwdriver or a knife. Those little plastic clips break easily, and there's a circuit board inside that you could damage. Before you know it, what should have been a simple battery change turns into ordering and programming a completely new key. And you'll be the one paying that bill, not the garage. All because of one little battery.
What about your spare key?
Don't forget about your spare key either. Its battery loses charge over time too, even if it's been sitting in a drawer and you've never used it. If you've had the key for years, change its battery as well. And keep it somewhere safe. Because if you lose your only key, getting a replacement becomes a lot more complicated and expensive.
A tip from Kris Mladenov: Always buy batteries from a reputable manufacturer and check the expiry date. Some cheap batteries are already flat before you've even opened the packet.
If you've changed the battery and your key still refuses to work, or you need a spare key, come and see us at Das Auto Service. We'll find out what's wrong and explain exactly what needs doing.
Further reading
- Electrical Problems and Control Modules
- Diagnostics at Das Auto Service
- Why Does Start/Stop Stop Working in Winter, and Why Does a New Car Battery Need Coding?
- Component Protection: Why Won't a Control Module from Another Car Work?
- Keyless Entry: Why Won't Your Car Detect the Key?
Frequently Asked Questions
Do I need to reprogramme my key after changing the battery?
Not with most Audi and VW keys. If it still doesn't work after changing the battery, bring it in and we'll take a look.
What battery does my Audi key use?
It depends on the key. Take out the old battery and check what's written on it. You'll find the exact battery type there.
How long does a car key battery last?
Usually a few years. Keyless keys tend to go through batteries faster because they're constantly communicating with the car.