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

Year

Exact model match

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

Author

Juan Carlos

Juan Carlos is a smart-home technician and workshop owner with years of retail consulting and sysadmin experience. He tests gear the way customers actually use it—and explains it without the jargon.