1Remove the hidden metal key
Press or slide the small release on the fob and pull out the emergency metal key. This often reveals the slot to open the case.
FREE REPAIR GUIDE
How to Replace a Key Fob Battery
Change your car key fob battery in 5 minutes with a coin. Find the right battery type and avoid dealer fees.
DIFFICULTYVery easy
ESTIMATED TIME~5 min
TOOLSCoin or small flat screwdriver
POTENTIAL SAVINGS$20–50Labour estimate · varies
Know what you’re replacing.
If you have to stand closer to your car for the remote to work, or your dash shows "key battery low", the fob needs a new coin-cell battery. It costs a few dollars and takes five minutes — no reprogramming needed on most cars.
What you’ll need.
CR2032 coin battery (multi-pack)The most common key fob battery · ~$6
View on Amazon →
CR2025 / CR2450 coin batteryUsed by some fobs — check the old one · ~$6
View on Amazon →Plastic pry toolAvoids scratching the fob · ~$6
View on Amazon →As an Amazon Associate, RepairAI may earn from qualifying purchases. Confirm fitment for your exact year, engine and trim before buying.
A little preparation first.
- Don't buy until you've opened the fob and read the code on the old battery (e.g. CR2032).
- Work over a table — the battery and tiny parts can roll away.
- Keep your other key handy in case something goes wrong.
One step at a time.
2Split the case
Put a coin or small flat screwdriver into the slot and twist gently. Work around the seam until the two halves separate.
3Find the battery
Note which side faces up (usually the flat side with the text) and read the battery code.
4Insert the new battery
Pop the old cell out with a fingernail or plastic tool, then press the new one in the same way up. Don't touch the circuit board with metal.
5Snap it shut and test
Press the halves together until they click all the way around, refit the metal key, and test lock, unlock and remote start.
Log in 
Troubleshooting
The fob still doesn't workThe battery is probably upside down, or a contact got bent — check both.Car says 'key not detected'Hold the fob against the start button (most cars have a backup reader there) and check the owner's manual.Buttons feel mushyThe rubber button pad may be out of place; reopen and seat it.
FAQ
How long does a fob battery last?Usually 2–4 years.Do I need to reprogram it?Almost never for a battery swap on most cars. If yours does, the owner's manual says so.
General guidance only. Procedures vary by year, engine and trim; if unsure, consult a qualified mechanic or your owner’s manual.