Mercedes-Benz CLS key fob battery
1 of the 18 model years listed for the Mercedes-Benz CLS have a proven battery. The most common answer is 2 x CR2025. Rows below run oldest to newest; a year can appear twice when the car came with more than one kind of key.
- 2006Unknown
Not confirmed yet
- 2007Smart key
Not confirmed yet
- 2008-2009Smart key
Not confirmed yet
- 2010Smart key
2 x CR2025
Owner's manual: manualslib.com (checked Nov 2, 2026)
Manual text: “always replace both batteries ... Lithium, type CR 2025”
Find CR2025 on Amazon - 2011Smart key
Not confirmed yet
- 2012-2018Smart key
Not confirmed yet
- 2019-2023Smart key
Not confirmed yet
Changing the battery
Smart key (push-button start)
- Start by freeing the hidden metal key: there is a latch or slide on the case, and the blade comes out once it moves.
- Use the slot where the metal key sat. Twist, do not lever hard, and work along the seam until the halves separate.
- Pop the old battery out with a toothpick or plastic pick, not a metal blade, and seat the new one with the + side matching the old one.
- Reassemble, refit the emergency key, and check that the car sees the fob when you press start.
On the common chrome Mercedes key, a slide at the back frees the mechanical key, and pushing that key into the opening releases the battery tray.
This key takes two CR2025 cells. Change both at the same time and stack them the way the old pair sat; mixing a fresh cell with a tired one shortens the life of the new one.
Coin cells are a choking and burn hazard for children. Store the spares in their original pack, out of reach.