Infiniti M35/M45 key fob battery
4 of the 5 model years listed for the Infiniti M35/M45 have a proven battery. The most common answer is CR2025. Rows below run oldest to newest; a year can appear twice when the car came with more than one kind of key.
- 2006Smart key
Not confirmed yet
- 2007-2010Smart key
CR2025
FCC ID CWTWBU735; CWTWBU618Two sites agree: uhs-hardware.com and americankeysupply.com (checked Nov 1, 2026)
Find CR2025 on Amazon
Changing the battery
Smart key (push-button start)
- Most push-button fobs hide a metal backup key. Press or slide its catch and draw the key out first.
- Look inside the empty key slot for a notch. Put the tip of the metal key or a small flat screwdriver wrapped in tape there and twist gently until the shell splits.
- Before you take the old cell out, look at its face. Put the new cell in with the same side showing, and avoid touching both faces at once.
- Reassemble, refit the emergency key, and check that the car sees the fob when you press start.
Infiniti Intelligent Keys normally hold a mechanical key behind a release knob; the slot behind it is where you pry.
A CR2025 is 20 mm across and 2.5 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.
Keep spare coin cells away from small children. A swallowed coin cell can burn the throat within hours; if it happens, go to an emergency room at once.