carfobbattery

smart fortwo key fob battery

8 of the 12 model years listed for the smart fortwo have a proven battery. The most common answer is CR2016. Rows below run oldest to newest; a year can appear twice when the car came with more than one kind of key.

  1. 2008-2015Key-head remote

    CR2016

    FCC ID KR55WK45144

    Two sites agree: uhs-hardware.com and fq101.co.uk (checked Nov 1, 2026)

    Find CR2016 on Amazon
  2. 2016-2019Key-head remote

    Not confirmed yet

Changing the battery

Key with remote in the head

  1. The remote electronics sit in the plastic head of the key itself, so there is no separate fob to open.
  2. Many key heads split along the side seam. Start at the small notch and pry a little at a time.
  3. Inside you may find a small circuit board in a tray. Lift the board out if the cell is underneath, swap the cell with the same side up, and refit the board.
  4. Close the head, check there is no gap, and try the buttons.

A CR2016 is 20 mm across and 1.6 mm thick. CR2032, CR2025 and CR2016 share the same width but not the same thickness, so a swap between them can leave a loose contact or a case that will not close.

If a child might have swallowed a coin cell, treat it as an emergency and get to a hospital right away.