How to Replace the Key Fob Battery in a Buick LaCrosse

1. Press the button on the back of the RKE transmitter and pull out the key.
2. Insert a flat tool into the bottom of the transmitter and separate it into two halves.
3. Push on the battery and slide it toward the bottom of the transmitter to remove it.
4. Insert the new battery with the positive side facing up and push it down until it is held in place.
5. Snap the battery cover back onto the transmitter.

• Replace the battery when the DIC displays a reminder message.
• Use a CR2032 or equivalent battery; it is not rechargeable.
• Do not touch the circuitry, because static from your body could damage the transmitter.

Source: 2019 Buick LaCrosse owner's manual, PDF page 36. 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.