Infiniti Q50 key fob battery

Smart key (push-button start)

1. Find the small release on the edge or back of the fob and hold it while you pull out the metal emergency key.
2. The gap left by the metal key usually has a pry point. A slow twist with a thin flat tool (tape on the tip saves the plastic) opens the two halves.
3. 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.
4. 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.

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.