Car Key Fob Stopped Working? What to Check First
By Mega Lock And Key · MD Locksmith License #394 ·
When a car key fob stops working, the most common cause is a weak coin-cell battery in the fob. Try a fresh battery and your spare fob first; if neither works, the fob may need reprogramming or replacing, which a mobile locksmith can usually do at the car.
Check these first
- The fob battery. Replace the coin cell (often a CR2032; check the battery you remove).
- Your spare fob. If the spare works, the problem is the first fob, not the car.
- The car battery. A weak car battery can stop the car from responding to any fob.
- Interference. Strong radio signals in some garages can block a fob. Try again away from the spot.
- Damage. Water, a cracked case, or worn buttons can stop a fob from working.
| Symptom | Likely cause | Next step |
|---|---|---|
| Buttons work only up close | Weak fob battery | Replace the coin cell |
| Spare works, main fob does not | Damaged or unpaired fob | Reprogram or replace the fob |
| No fob works, dash is dim | Weak car battery | Charge or replace the car battery |
| "Key not detected" on a push-to-start car | Fob battery or fob fault | Hold the fob at the backup spot to start, then replace the battery |
Starting a push-to-start car with a dead fob
Most push-to-start cars have a backup spot where the car can read a fob with a dead battery: on the steering column, in the console, or against the start button itself. Your owner's manual shows where. The hidden blade in the fob opens the driver's door.
When the fob needs a locksmith
If a fresh battery does not fix it, the fob may have lost its pairing or failed. We test the fob, reprogram it if it is sound, or program a replacement at the car. See key fob programming in Baltimore.