How to Replace the Key Fob Battery in a Honda Civic Hatchback

1. Remove the built-in key from the smart entry remote.
2. Pry off the upper half of the cover carefully at the edge with a coin.
3. Wrap the coin in a cloth so it does not scratch the remote.
4. Take care not to lose the buttons as you open it.
5. Replace the battery, making sure the polarity is correct.

• Smart entry remote battery type: CR2032.
• Master key with remote transmitter uses a CR1620 battery and is opened with a small Phillips-head screwdriver and a small flat-tip screwdriver.
• Replace the battery if the indicator does not come on when the button is pressed.

Source: 2021 Honda Civic Hatchback owner's manual, PDF pages 625, 624. 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.