Why is my key fob not working?
A smart key is a small radio transmitter with a battery. Before you assume it needs replacing, match what you're seeing here:
| What happens | Likely cause | Try this first |
|---|---|---|
| "Key not detected", or you have to hold the fob close to the car | Weak fob battery | Replace the coin cell. The number (often CR2032 or CR2450) is printed on the old one. |
| Buttons only work if you press hard | Worn button pads or a cracked case | A new shell often fixes it. See below. |
| One fob works and the other doesn't | Dead battery or a damaged fob | New battery. If it's still dead, that fob may need replacing. |
| Fob went through the wash or got soaked | Water on the circuit board | Take the battery out and let it dry completely. Sometimes it comes back. |
| Neither fob is detected | Weak car battery or a fault in the car | Check if the dash lights and headlights are dim. A low car battery causes strange keyless problems. |
Change fob batteries every couple of years, ideally in the fall. Cold weather drains a weak coin cell fast, and a January morning in a Toronto parking lot is a bad time to find out.
How do I start my car if the smart key battery is dead?
You can almost always still get in and drive. Smart keys have a backup for exactly this:
- Press the release on the fob and slide out the hidden metal key.
- Use it on the driver's door. On many cars the keyhole sits under a small cap on the handle that pops off from underneath.
- Press the start button using the fob itself, or put the fob in the backup slot if your car has one. Your owner's manual shows the exact spot.
This works because the fob has a backup chip the car can read at very close range, even with a dead battery. The alarm may go off when you open the door with the metal key. Starting the car usually stops it. If none of this works and you can't get in, that's a car lockout and we can open it for you.
Need smart key & fob replacement now? A real person answers 24/7.
Call (647) 367-8113Can you replace a lost push-to-start key?
Yes, for most cars on Toronto roads, including Toyota, Honda, Hyundai, Kia, Nissan, Mazda, Subaru, Ford, Chevrolet, GMC and Jeep. We supply the right fob for your car, program it to start the car and work the doors, and cut the emergency blade that slides into it. If your car has a key with buttons instead of a start button, see transponder key programming.
If you've lost every fob, it's an all-keys-lost job, so have your ownership, photo ID and VIN ready. Car key replacement explains how that works. Some European luxury brands and some very new models can only get fobs through the dealer, and we'll tell you on the phone if yours is one of them.
When we program the new fob, we can remove the lost one on most cars, so it won't open or start the car if someone finds it.
Original or aftermarket fob: which one should I get?
- Original (OEM) fob: the same part the dealer uses. Best fit, best range, and it costs more.
- Aftermarket fob: made to work with your car for less money. Quality varies, and some have weaker range or buttons that feel cheap.
Not every car has a good aftermarket option. We'll tell you which ones exist for your car and the price of each, and you choose.
Can you fix a cracked fob or worn buttons instead of replacing it?
Often, yes. The electronics inside a fob usually outlast the plastic. If the case is cracked, the rubber buttons are worn through or the key ring loop snapped off, we can move the circuit board into a new shell. The fob stays programmed, so nothing has to be redone with the car.
A new shell won't help if the board itself is broken or corroded from water. Then a new fob is the fix.
Keyless car theft has been a real problem in Toronto. At home, keep fobs away from the front door, or in a signal-blocking pouch, so thieves can't pick up and relay the signal to open and start your car.
What happens when you call?
Tell us what the fob is doing
Lost, dead, cracked, or a warning on the dash. Plus the year, make and model.
Pick the fix
Dispatch tells you if a repair might work, which replacement fobs fit, and the price of each.
Program at the car
We check ownership, program the fob, cut its emergency blade and remove any lost fobs.
Test it the way you use it
Walk-up unlock, push-to-start, buttons and trunk, all checked with you before we go.
Page reviewed October 2026 by the LocksmithGT team.