Mazda 6 sedans with keyless entry are equipped with a switchblade key, which integrates the car key and the remote entry system into one unit. If the battery fails, you'll need to open the switchblade key to replace it. Mazda recommends using a lithium CR1620 battery. It only takes a few minutes to open the 2006 Mazda 6 switchblade key.
Place the key on a flat surface. Press the silver button on the switchblade fob to open the key.
Hold the fob with the key blade pointing to the left, and the silver button facing away from you. Examine the bottom side of the switchblade fob for a small tab. The tab is located within the cavity that the switchblade key folds into. Push the tab with a small flathead screwdriver. With the tab depressed, pull the key half of the fob away from the remote unit to separate the two parts.
Insert the screwdriver into the exposed part of the switchblade fob (where the key unit was attached). Gently pry open the switchblade fob by separating the two halves with the screwdriver. Opening the switchblade fob gives you access to the battery and circuit board.
To reassemble the switchblade key, push the two halves of the fob back together until they snap in place. Reattach the key half of the fob by pushing the key and remote units firmly together until locked in position.
If you are replacing the battery, set the battery with the positive symbol facing down.