When your Audi key fob battery dies, use the hidden emergency key blade to manually unlock the driver's door, then place the dead fob on the backup start location (typically in a cup holder or on the center console) to start the vehicle[1]. The CR2032 battery used in most Audi key fobs costs $3–$8 and takes less than 5 minutes to replace without special tools[2].
Before your key fob stops working completely, watch for these warning signs[2]:
Most Audi key fob batteries last 2–3 years under normal use[2]. Heavy usage or extreme temperatures can shorten this lifespan. If you experience your Audi key's red light blinking but the car not opening, a dead battery is likely the cause.
Every Audi key fob contains a hidden mechanical key for emergencies[1]. Retrieving and using this key is straightforward.
Locate the two small buttons on either side of the key fob near the keyring loop[3]. Squeeze both buttons simultaneously and pull the chrome or metal end piece away from the fob. The mechanical key blade slides out, revealing a traditional flat key[3].
The keyhole location varies by model[1]:
Once unlocked, the alarm may sound briefly because the car detects entry without the proximity signal[1]. This is normal and will stop once you start the vehicle.
After getting inside, starting the vehicle requires placing the dead fob on a specific backup location where the car can inductively read the key's transponder[1]. The location varies by model and year.
| Model/Year | Backup Start Location |
|---|---|
| Early models (2007–2015) | Dashboard slot or steering column mark |
| A3, Q3 (2020+) | Front cup holder |
| A5 (2018) | Driver's side cup holder |
| A5, A6 (2019+) | Front of center console storage area |
| A4, S4 (2023+) | Center console, in front of storage area |
| Q5 (2018–2020) | Cup holder |
| Q7 (2007–2008) | Traditional ignition switch (use mechanical key) |
| Q7, Q8 (2019+) | Front cup holder or slot between cup holders |
| e-tron GT | Rear cup holder |
Look for a small key symbol with radiating lines—this mark indicates the backup start location[1]. Place the fob directly on this symbol, press the brake pedal firmly, and push the start/stop button[3].
If the car doesn't start on the first try, reposition the fob slightly and press the brake pedal harder[1]. Some models require the brake pedal to be pressed very firmly to engage the release switch[1].
Battery replacement requires no tools for most Audi key fobs and takes under 5 minutes[2].
No reprogramming is required after battery replacement[4]. The key fob should work immediately. If it doesn't respond, double-check the battery orientation.
| Audi Model | Battery Type | Compatible Years |
|---|---|---|
| A3 (all variants) | CR2032 | 2015–2025 |
| A4, S4, A4 Allroad | CR2032 | 2005–2025 |
| A5, S5 | CR2032 | 2008–2025 |
| A6, S6, A7, S7 | CR2032 | 2012–2025 |
| A8, S8 | CR2032 | 2010–2025 |
| Q3 | CR2032 | 2015–2025 |
| Q5, SQ5 | CR2032 | 2009–2025 |
| Q7, SQ7 | CR2032 | 2017–2025 |
| Q8, SQ8 | CR2032 | 2019–2025 |
| TT, TT RS | CR2032 | 2016–2025 |
| e-tron models | CR2032 | 2019–2025 |
Some older models (pre-2017) or certain key fob designs may use CR2025 batteries[2]. When in doubt, check the battery currently installed in your fob or consult your owner's manual.
CR2032 batteries are widely available and inexpensive[2]:
Choose name-brand batteries for best longevity. Quality batteries can extend fob life to 3+ years[4]. If you're also exploring what the Audi Advanced Key offers, maintaining fresh batteries ensures all keyless features work reliably.
While battery replacement is DIY-friendly, certain situations warrant dealer or locksmith assistance:
Replacement key fobs from Audi dealerships cost $300–$500 including programming[5]. If you need car key fob replacement services, independent automotive locksmiths often charge less.
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