Changing the Battery in Your Mazda 3 Key Fob

There's nothing more annoying than getting in your car after a long and tiring day and discovering that your key fob battery is dead. This is a straightforward fix that can be found at a big box retailer or at a hardware store.

A spare key fob for your Mazda 3 is an inexpensive alternative to not having to take it to a dealer to have them re-program the keys.

Battery Replacement

The battery replacement in the mazda 2 key replacement 3 key fob is an easy process that can do at home. But, you should only replace the battery if it dies, or if the key fob shows a message on the multi-information display saying, "Low key fob battery. Replace battery."

To open the key fob's casing it requires a tape-wrapped flathead screwdriver and a bit of patience. Place the flathead screwdriver's head in a notch, or gap on the bottom of the metal of the Mazda 3 key fob to take off the lower portion. Repeat this process for the top metal piece however, be careful not to scratch the rubber ring that is at the bottom of the key fob's case.

When the fob case is open, you'll be able to see a slot on either side of the case, which houses the battery. Use the flathead screwdriver with tape to gently pry the case open, beginning on one side and then shifting to the other. Remove the old battery and put in a new CR2025 ensure that it's face-up for proper polarity. Install the cap on the battery the other side and attach both sides of your key fob case by pressing until they click.

Once you've replaced your battery check the fob to make sure it is working by locking and unlocking your doors. If everything is in order then you can begin using the Mazda 3's remote functions for the first time!

Pairing Issues

This could be a sign that the transmitter in your car may have been damaged. This is usually a matter of an expert to repair it and may need a new key fob.

If you've tried replacing the battery and reprogramming the key fob but has not solved the problem it is possible the chip in the key fob is faulty. This could be the case if the keyfob has been dropped or exposed to saltwater or the touch of dirty fingers.

To determine the cause of the issue, you will need to locate a small "key" embedded in the edge of the fob that allows you to lift it open and take out the circuit board. You will then be able to look for any damage or corrosion on the chip. It is recommended to clean the paper towel to keep the microchip from being damaged.

If you're not sure, you can also check the battery connector terminals for cracks or breakage. If this is the situation you can solder the terminals back into place will typically restore the functionality of the key fob. You can also check the buttons for damage or wear. If the buttons are loose, they can easily be soldered back in place in the event that the button is physically snapped off.

Interference Signals

There's nothing more frustrating than trying to start your car and seeing the message "No Fob Detected". This happens at the worst time, for instance the time you're late to work or pick up your children from daycare or school. The good thing is that there are steps you can follow to resolve the issue and determine the cause.

Interference signals can cause the remote key fob to cease working properly. This can be caused by objects such as weather conditions, buildings, and mazda 3 Key transmitters that operate on the same frequency. Interference can also occur when you have an aftermarket device installed in the vehicle that transmits at the same frequency as the key fob.

The key fob can also be damaged if exposed to salt water or water. The rubber seals on the chip's electronic components can be damaged by water, particularly if it is submerged for an extended period of time, such as in a pool or at the beach. This could cause the chip's function to cease, requiring replacement of the key fob. If you own a programmable key, you can clean the chip with isopropyl alcohol or an electronic cleaner to help it return to working. If this does nothing you can be sure that the chip is fried and must be replaced.

Locking/unlocking the Doors

The buttons on the key fob transmit electronic signals to the solenoid inside the car, which then converts this signal into mechanical action. It locks and unlocks doors. If the door lock isn't working it could be because of an issue with the solenoid. This will require professional auto repair shops to examine.

A dead 12 volt can also stop the fob from functioning effectively. This happens when the battery loses its charge or if the contactors become corroded and stop conducting electricity. The good news is that a new battery is able to fix this issue in just minutes.

The receiver module may be the cause of the issue if the key fob doesn't work after replacing batteries or reprogram the device. The device receives radio frequency signals from the key fob and Mazda 3 Key interprets them to control the functions of the vehicle. If it fails it could cost a lot to repair.

To determine if this is the case, start by inserting your spare key into the key slot and turning the ignition to ON. Press the key fob button three times within 10 seconds without removing it. The Mazda 3 system will now sync the key to the car, and you can use it as your primary remote for driving. This lets you program up to three keys.