Mazda Key Fob Battery Replacement

Being unable to unlock your car because of a dead key battery can be a frustrating experience. The good thing is it only takes a few steps to replace the dead battery and get back on the road.

Signs That A Key Fob Battery Is Dying

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In the past, key fobs usually had a small LED that would flash when the button was pressed. Modern key fobs generally don’t have this feature. If your Mazda has keyless entry, the first time you will notice key fob battery issues is when the car refuses to unlock as you pull on the door handle. The following signs all point to a failing key fob battery:

  1. You have to press the unlock button many times for the car to unlock
  2. The key only works in very close proximity to the car
  3. The keyless entry feature stops working or only works occasionally

If your car has been struggling to start or you recently left the lights on overnight, the fault may be with the vehicle’s battery and not the key fob.

What To Do In An Emergency

Finding out that your key fob battery is dead at home is all well and good, but what if you are stuck at work or at a gas station? As a short-term solution, you can complete the following steps:

  1. Look for a small latch on the back of your key fob.
  2. Press the latch and then pull it down.
    1. If your Mazda key fob won't open, use a small flat head screwdriver.
  3. You'll find a physical key inside the fob.
  4. Unlock the driver’s side door with this key and then reinsert it into the fob.
  5. Once seated, press the brake pedal while holding the Mazda symbol up against the start button.
  6. This should send a signal to the car that will start the engine.

Replacing the Key Fob Battery

Image Credit: PaulsTravelPictures

A typical modern Mazda key is made up of the following components:

  • Metal or plastic housing with three to four buttons
  • Electronic board and small battery
  • Traditional key hidden within the housing

Take these steps to open your Mazda key fob and then replace the battery:

  1. Look for a small latch on the back of your key fob.
  2. Release the latch by pressing it and then pulling it down (or use a small flat head screwdriver).
  3. Remove the physical key inside the housing.
  4. There will be two slots inside where the key was secured. Rotate a flat head screwdriver gently in each slot to help separate the two halves of the key fob.
  5. Use the screwdriver to continue to pry apart the two sections along the outside.
  6. Once open, you will see a circular battery cover. Remove this and take note of the battery type. (Most Mazda key fobs use a CR-type battery that looks like a thin round disc, frequently referred to as coin batteries. Common types are CR2025, CR2032 and CR1620. Using the incorrect type may work temporarily, but you should stick to the manufacturer’s recommendations.)
  7. Once you have replaced the battery, refit the circular battery cover and press the two halves of the key fob together. Insert the physical key and you should be ready to go.

If your Mazda key fob won't work at this point, you may need to reprogram it. This tutorial will walk you through the process.