How to Disassemble a 408 Key?

[StEva]

Insert a small screwdriver into the groove of the key, pry open the back cover of the remote, remove the back cover of the remote, and you can see the circuit board and battery inside. If you want to replace the key battery, remove the depleted battery and install a new one, then reassemble the remote cover.

[AnastasiaAnn]

Last year, I drove a Peugeot 408 and happened to have the key battery die, so I replaced it myself. The process is simple: first, locate the groove on the back of the key—usually, there's a seam near the logo. Gently pry it open with a fingernail or a small screwdriver, applying even pressure to avoid scratching the plastic casing. Once separated, you'll see a small battery slot, typically for a CR2025 battery. Remove the old battery and replace it with a new one. When reassembling, ensure the clips align and press firmly until you hear a 'click' to secure it. Doing it myself saved me a trip to the repair shop. The key battery lasts about two years, so make it a habit to check regularly to avoid accidentally being unable to lock the car. If you can't pry it open, don't force it—use professional tools for a safer approach.