How to Replace the Key Fob Battery in a Lincoln MKX

1. Remove the backup key from the transmitter.
2. Twist a thin coin in the slot hidden behind the backup key slot to pop off the battery cover.
3. Take out the old battery.
4. Insert the new battery, following the orientation shown inside the IA key, and press it down until fully seated.
5. Snap the battery cover back onto the transmitter and install the backup key.

• Uses one coin type three-volt lithium battery CR2032 or equivalent.
• Do not wipe grease off the battery terminals or the back of the circuit board.
• Replacing the battery does not de-program the IKT or IA key from the vehicle.

Source: 2011 Lincoln MKX owner's manual, PDF page 104. Steps are summarized in our own words (AI-assisted, checked against the cited pages 2026-10-18). Other model years can differ; your manual has the final word.