You press the button and nothing happens. Before you assume the worst, know that a dead fob battery is the most common reason a key fob stops working, and in most cars you can still get in and drive away. Here’s what to do.
Signs your fob battery is running low
- You have to be closer to the car than usual for the buttons to work
- You need to press a button more than once
- Your dashboard shows a “key not detected” or “key battery low” message
- The car sometimes doesn’t recognize the key when you push the start button
Step 1: Use the hidden emergency key
Most smart fobs have a small mechanical key blade tucked inside. Look for a sliding latch or release button on the fob, then pull the blade out.
On many newer cars, the driver’s door keyhole is hidden under a plastic cap on the door handle. Look for a small slot on the underside of the cap, gently pry it off with the tip of the key blade, and unlock the door.
Opening the door with the key may set off the alarm. That’s normal. It should stop once the car recognizes the fob in the next step.
Step 2: Start the car with a dead fob
Push-button start cars can usually still read a fob with a dead battery if it’s held in exactly the right spot, because the chip inside doesn’t need battery power at close range. Common methods include:
- Holding the fob directly against the start/stop button while you press the brake and push the button
- Placing the fob in a marked slot or pocket in the center console, glove box or under a cup holder mat
The exact location varies by make and model, so check your owner’s manual (search for “key battery discharged” or “emergency start”).
Step 3: Replace the battery
- Open the fob case, usually at a seam or with a small notch. The emergency key blade often works as a pry tool.
- Note which side of the old battery faces up before removing it.
- Check the number printed on the battery. Many fobs use a CR2032, but CR2025 and CR2450 are also common.
- Insert the new battery the same way, snap the case closed and test the buttons.
Florida heat and fob batteries
High temperatures can shorten battery life, and a fob left in a hot car all summer may drain sooner. If you rely on one fob, keep a spare battery in your glove box.
When a new battery doesn’t fix it
If the fob still doesn’t work after a fresh battery, or you don’t have the fob at all, it’s time to call a locksmith. Common causes include:
- A fob that was dropped, got wet or has a damaged circuit board
- A fob that has lost its programming to the vehicle
- A worn or broken emergency key blade
- Lost keys, with no spare
We cut and program replacement keys and push-to-start fobs at your vehicle, typically in 20–35 minutes, without a tow or a dealership appointment. You’ll need a photo ID and proof of ownership. Call (239) 412-2998.