How to Change the Battery in a 2015 Lincoln MKZ Key Fob

The 2015 Lincoln MKZ uses a proximity key fob — the type that allows keyless entry and push-button ignition without physically inserting a key. Like all battery-powered devices, the fob's battery will eventually drain. When it does, you may notice delayed door response, reduced range, or a low-battery warning on the dashboard. Replacing the battery is a straightforward DIY task that takes a few minutes and costs less than most anything else on a vehicle.

What Battery Does the 2015 MKZ Key Fob Use?

The 2015 Lincoln MKZ key fob typically uses a CR2032 coin-cell battery — a flat, round, 3-volt lithium battery widely available at grocery stores, pharmacies, hardware stores, and auto parts retailers. Prices generally run between $2 and $6 for a single battery, though multi-packs are often available at lower per-unit cost.

CR2032 batteries are shelf-stable for several years when stored properly, so buying in small quantities is fine. Always use a fresh battery from sealed packaging — loose or previously installed batteries may already be partially discharged.

What You'll Need

• One CR2032 battery
• A small flat-head screwdriver (or a coin)
• A soft cloth or paper towel (optional, to protect the fob's finish)

No special tools are required.

Step-by-Step: Opening the Fob and Swapping the Battery 🔋

Step 1: Remove the emergency key blade. On the back or side of the MKZ fob, there's a small release button or slider. Press or slide it to release the hidden emergency key blade tucked inside the fob. Pull the blade out and set it aside.

Step 2: Locate the fob seam. With the key blade removed, you'll see a seam running around the edge of the fob casing. This is where the two halves of the shell separate.

Step 3: Pry open the fob. Insert a small flat-head screwdriver into the seam at the slot where the key blade was stored — this is typically the easiest entry point. Gently twist or lever the screwdriver to separate the two halves. Work slowly around the seam if needed. Avoid using excessive force; the plastic clips are firm but can break if pried at the wrong angle.

Step 4: Locate and remove the old battery. Once open, the CR2032 battery sits in a circular holder on the circuit board. Note which side faces up — the positive (+) side typically faces up, but confirm before installing the new one. Use the screwdriver tip or your fingernail to pop the old battery out of its retaining clip.

Step 5: Install the new battery. Place the new CR2032 with the correct orientation (positive side up, matching how the old battery was seated). Press it firmly into the clip until it snaps into place.

Step 6: Reassemble the fob. Align the two halves and press them together firmly until you hear or feel the clips snap closed. Reinsert the emergency key blade until it clicks into place.

Step 7: Test the fob. Stand near your vehicle and test the lock, unlock, and remote start buttons (if equipped). Check the range from a normal distance — it should respond without delay.

What Can Go Wrong

If the fob remains unresponsive after a correct battery replacement, the unit may need to be reprogrammed to the vehicle. Lincoln MKZ fobs are coded to the specific car. Reprogramming can sometimes be done through a self-sync process, but depending on the situation, it may require a dealer or locksmith with the appropriate scan tool.

A Note on Fob Condition and Age 🔑

Battery replacement assumes the fob's internal components are in working order. Fobs that have been dropped, submerged in water, or heavily worn may have circuit damage that a battery swap won't fix. If the fob's buttons feel mushy, the casing is cracked, or it's been through any physical trauma, the battery may not be the only issue.

The 2015 MKZ came with two key fobs from the factory. If one fob is failing while the other still works normally, that's a strong indicator the problem is isolated to the failing fob rather than the vehicle's receiver system.

When More Than a Battery Is Involved

Some owners assume a dead fob means an expensive fix. In most cases it doesn't — but there are situations where the problem runs deeper. A fob that drains batteries unusually fast, one that was never programmed after a prior repair, or one purchased as an aftermarket replacement may require additional steps beyond a simple battery swap.

Your specific fob behavior, the condition of the fob itself, and whether it's the original factory unit all affect what the right next step looks like — and that's where your own situation matters more than any general guide can account for.