
To open the Mazda 3 key and replace the battery, follow these steps: 1. Press the remote key button to remove the mechanical key; 2. Use a tool to pry open the back cover along the middle seam of the key; 3. Remove the old battery to replace it. Taking the 2020 Mazda 3 as an example, it belongs to the compact car category with body dimensions of 4662mm in length, 1797mm in width, and 1445mm in height, with a wheelbase of 2726mm and a fuel tank capacity of 50 liters. The 2020 Mazda 3 features a MacPherson strut front suspension and a torsion beam rear suspension. It is equipped with a 1.5L naturally aspirated engine, delivering a maximum horsepower of 117PS, a maximum power of 86kW, and a maximum torque of 148Nm, paired with a 6-speed manual transmission.

I've been driving my Mazda Axela for several years, and changing the key battery myself is quite simple. On the back of the key, you can see a small groove. Use a thin plastic card or the edge of a coin to gently pry it open—do it slowly and don't use too much force, or you might scratch the casing. Once opened, lift the cover to reveal the round coin battery inside, usually a CR2025 model. Be careful when removing the battery to avoid pulling on the small contacts. When installing the new battery, remember to place it with the printed side facing up and insert it directly into the slot. Before closing the cover, make sure all parts are aligned, then press firmly until you hear a click. After replacing, press a key button—if the light turns on, it's working. You can buy the battery at a supermarket or online for just a few dollars, saving you the cost of going to a shop. It's recommended to check the battery status annually and replace it when the remote sensing weakens. Keep a spare key in the car to avoid locking yourself out in case of a mishap.

Replacing the Mazda 3 key battery requires careful operation. I helped a friend replace it last time. First, locate the small gap on the back and gently pry it open with a fingernail or plastic pry tool—avoid using metal tools to prevent short circuits. After opening, remove the old battery, which is a CR2025 model. When installing the new battery, pay attention to the orientation with the plus sign facing outward. Wash your hands to prevent static electricity before testing the functions. Conduct the entire process in a quiet environment with gentle movements to avoid damaging the internal circuits. If you're not skilled, it's best to visit a repair shop and let a professional handle it—they have all the necessary tools to avoid mistakes. The battery typically lasts one to two years, so it's advisable to keep a spare battery ready. After the operation, check the response of the unlock button and replace the battery early if the signal weakens.

As a daily driver, I've replaced the key battery for my Mazda3 several times. Flip the key over to find a small opening on the back, then use a fingernail or thin tool to pry it open. The battery inside is a CR2025 - make sure not to get the wrong model. When installing the new battery, ensure it's placed with the positive side facing up. Test the key after reassembly. The whole process is quick and simple, just remember to handle it gently.


