Changing the Battery in Your Mazda 3 Key Fob

There's nothing more frustrating than getting in your vehicle after a long day, and discovering that the key fob battery is dead. This is a straightforward solution that can be accomplished at a big box retailer or at a hardware store.

A spare key fob for your Mazda 3 is an inexpensive option to not have to be towed to a dealership in order to have them reprogram the keys.

Battery Replacement

The battery replacement in your Mazda 3 key fob is a simple process that you can do at home. It is recommended to replace it when the battery goes out or if you get a message that reads "Low keyfob battery" on the multi-information display. Replace battery."

You'll need to use a flathead screwdriver with tape and patience to open the case. Put the head of the flathead screwdriver into a notch, or gap on the bottom metal of the Mazda 3 key fob to remove the lower part. Repeat the process for the top metal piece however, be careful not to damage the rubber ring that is on the bottom of the case.

When the fob case is open, you'll be able to see the slots on either side of the case, which houses the battery. Use the tape-wrapped flathead screwdriver to gently pry open the case, starting with one side and moving to the next. Take out the old CR2025 and replace it with a brand new one, making sure to put it on its face to ensure proper the polarity. Attach the cap to the battery again and secure both sides of your key fob case by pressing until they click.

After replacing the battery Check the fob to ensure it's working by locking and unlocking your doors. If everything appears to be working then you can begin using your Mazda 3's remote capabilities for the first time!

Pairing Issues

If your key fob stop working all of a sudden it could be a sign that the transmitter in the car has been damaged. It's usually a task to a professional and you require a new key fob.

If you have tried replacing the battery and reprogramming the key fob but has not solved the problem it is possible that the chip inside the key fob is malfunctioning. This can happen when the key fob was dropped on hard surfaces and exposed to salt water, or even touched by dirty hands.

You'll need to locate a small "key" that is built into the seam to remove the circuit board to identify the issue. You can then examine the electronic chip for corrosion or damage. It is recommended to use a clean towel to avoid damaging the microchip.

You can also examine the battery connector's terminals and examine if they're damaged or cracked. If this is the case, carefully reconnecting them will usually restore the function of the key fob. You can also check the buttons for damage or wear. If they are loose, they can be resoldered into place unless one has physically snapped.

Interference Signals

There are few things more frustrating than staring at an "No Fob Detected" message when trying to start your car. It usually happens at the most awkward time, such as when you're late for work or when you have to pick up children from daycare or school. There are some things you can do to troubleshoot and find out the root of the issue.

Interference signals can disrupt the remote key fob's signal to the vehicle and cause it to not function correctly. This can be caused from things like weather conditions, buildings and transmitters that operate on the same frequency. Interference may also occur if you have an aftermarket device installed in your vehicle that transmits on the same frequency as the key fob.

The key fob might be damaged if exposed to water or salty water. The rubber seals on the chip's electronic components can be damaged by water, especially when it is submerged over an extended period of time such as in a pool or ocean at the beach. This could cause the chip to stop functioning, requiring replacement of the key fob. If you have a programmeable key, you can clean the chip with isopropyl Alcohol or an electronic cleaner to help it return to functionality. If this does not work the chip, it's likely fried and will need to be replaced.

Locking or Unlocking the Doors

The buttons on the fob's key send electronic signals to the solenoid in the car, which transforms the signal into mechanical action. This locks and unlocks doors. If the door lock is not working, it may be a solenoid issue that requires investigation with the help of an expert auto repair shop.

A dead 12 volt battery could cause the fob to stop functioning properly. This can happen if the battery's charge is lost or if the contacts get corroded and stop transferring electricity. This issue can be solved in minutes with a new battery.

If the key fob isn't working after changing the battery or try to program it again the problem could be with the receiver module. The device receives radio frequency signals from the key fob and interprets them to control the functions of the vehicle. It could be expensive to repair if it malfunctions.

To confirm if this true, put your spare key into the key slot. Then turn the ignition on. Press the key fob two times for 10 seconds without taking it out. The mazda key fob 3 system synchronizes the key to the vehicle and you can now use it as your primary driving remote. You can program up to three keys in this way.