Volkswagen Jetta key fob battery

Key with remote in the head

1. This type has the buttons built into the key head. The cell is inside that head, between two clipped halves.
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. The coin cell is usually under or on the back of a small board. Keep the rubber button pad in place while you swap the cell.
4. Snap it closed and press each button. The car still starts with a dead remote battery on most of these keys, because the start chip needs no battery.

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.

Flip key

1. Open the flip blade. Never force the hinge sideways, since the spring and pin are the weak part of a flip key.
2. Look along the edge for a notch. A coin turned in that notch usually separates the remote half from the blade half.
3. Take out the old cell, noting which side faced you, and fit the new one the same way.
4. Press the halves together until no gap shows, then try every button.

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.