Volvo S40 (P1) key fob battery
4 of the 8 model years listed for the Volvo S40 (P1) have a proven battery. The most common answer is CR2032. Rows below run oldest to newest; a year can appear twice when the car came with more than one kind of key.
- 2004Key-head remote
Not confirmed yet
- 2005Key-head remote
CR2032
FCC ID KR55WK49250; KR55WK49259Owner's manual: manualowl.com (checked Nov 2, 2026)
Manual text: “the battery (type CR 2032, 3V) is weak”
Find CR2032 on Amazon - 2006Key-head remote
Not confirmed yet
- 2007Key-head remote
CR2032
FCC ID KR55WK49250; KR55WK49259Two sites agree: manualowl.com and fcpeuro.com (checked Nov 1, 2026)
Find CR2032 on Amazon - 2008Key-head remote
CR2450
FCC ID KR55WK49250; KR55WK49259Owner's manual: manualowl.com (checked Nov 2, 2026)
Manual text: “the battery (type CR 2450, 3V) is weak”
Find CR2450 on Amazon - 2009Key-head remote
Not confirmed yet
- 2010Key-head remote
CR2450
FCC ID KR55WK49250; KR55WK49259Two sites agree: manualowl.com and fcpeuro.com (checked Nov 1, 2026)
Find CR2450 on Amazon - 2011Key-head remote
Not confirmed yet
Changing the battery
Key with remote in the head
- This type has the buttons built into the key head. The cell is inside that head, between two clipped halves.
- Find the seam around the head. Twist a coin or small flat screwdriver in the notch at the blade end or side until the halves part.
- 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.
- Close the head, check there is no gap, and try the buttons.
A CR2032 is 20 mm across and 3.2 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.
A CR2450 is 24.5 mm across and 5.0 mm thick, much fatter than a CR2032. A thinner cell will rattle and lose contact, so buy the exact size.
Coin cells are a choking and burn hazard for children. Store the spares in their original pack, out of reach.