Nissan Maxima key fob battery

Separate remote fob

1. The remote is a small standalone unit. You will not need to touch the ignition key at all.
2. Turn it over: some older fobs use one small screw, newer ones just clip. Pry at the seam once any screw is out.
3. Swap the cell or cells, keeping the same side up as the old ones.
4. Close the fob and test it. If it does not work, open it again and check the cell is seated flat.

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.

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. 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.
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. Press the head together until it clicks and test the buttons. The transponder chip that lets the car start is separate from the battery, so starting should not change.

A CR1620 is 16 mm across and 2.0 mm thick. It is easy to confuse with the 20 mm CR20xx sizes, which will not fit.

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. 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.
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. Snap the halves back together, slide the metal key home, and press each button, then try the start button from the driver's seat.

Nissan Intelligent Keys normally hold a mechanical key behind a release knob. With the key out, a small screwdriver in the slot separates the halves.

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.