Acura TL key fob battery

Separate remote fob

1. A separate fob has no key blade inside, so it opens with nothing but a coin or a small screwdriver.
2. Find the slot along the edge and turn a coin in it. Go slowly so the clips do not snap.
3. Replace the cell, keeping the + side where it was, and check the small metal tab still touches it.
4. Reassemble and test from a short distance.

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. Here the key blade and remote are one piece. You open the plastic head, not the blade.
2. Work a thin flat tool into the seam near the blade and twist; go round slowly if it does not open at once.
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. Close the head, check there is no gap, and try the buttons.

A CR1616 is 16 mm across and 1.6 mm thick. It is easy to confuse with the 20 mm CR20xx sizes, which will not fit.

Smart key (push-button start)

1. Start by freeing the hidden metal key: there is a latch or slide on the case, and the blade comes out once it moves.
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. 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.
4. Reassemble, refit the emergency key, and check that the car sees the fob when you press start.

Acura smart keys usually open the same way as Honda's: release the built-in key, then twist in the slot.

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.