Contents
How to use the Car Key Fob Battery Finder
- Type your make, model, and year (e.g., Aufi a4 b9 / Ford F-150 2018).
- The table instantly shows the correct battery type and your car’s generation/body.
- Click the battery code (CR2032, CR2450, etc.) to open an Amazon search.
- Toggle Exact model match if your model name is long or has trims.
- Tip: If your year spans a range, enter it as 2015-2018.
| Make | Model | Years | Body/Generation | Battery |
|---|
Key fob battery replacement (quick guide + safety)
A dying fob usually means shorter range, “Key Not Detected” messages, or needing multiple presses. Follow these quick steps to replace the key fob battery safely.
Before you start
- Check your owner’s manual or our Car Key Fob Battery Finder for the exact battery (CR2032, CR2450, CR2016, etc.).
- Work on a clean surface. Avoid static; touch metal first.
- If your fob is water-resistant, opening it incorrectly can compromise the seal—replace the gasket if damaged.
- Some BMW/Mercedes “rechargeable” keys use VL cells and may require soldering; if noted, use a pro.
Step-by-step
- Remove the emergency blade (small mechanical key) and locate the seam.
- Split the case with a plastic tool or coin—no metal prying on the PCB.
- Note battery orientation (+/–). Take a photo, then swap the cell.
- Avoid fingerprints on the new battery; oils reduce contact.
- Reassemble carefully. Ensure clips snap and the gasket sits flat.
- Test: Lock/unlock, then start. Some cars need a resync—stand near the car and press Lock/Unlock a few times, or follow manual instructions.
When to see a pro
- The fob is glued/ultrasonically welded, or the board is labeled VL/ML (rechargeable).
- Push-to-start still says Key Not Detected after a fresh battery.
- Water damage, broken buttons, or case won’t close.
Good to know
- Dispose of old cells at a battery recycling point—don’t toss in trash.
- Keep coin cells away from children and pets (choking/ingestion hazard).
- Carry the emergency blade; it can unlock the driver’s door if the fob dies completely.
How to Dispose of Old Batteries the Right Way
