ND - Replacing Key Fob battery

Technical Area Electrics & ICE
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  1. My model of MX-5 is: ND4

Hi all, just given the Mazda a quick engine run as it has not been used much, and I am getting a “keyfob battery” low message on the dash.

The car is only about 18 months old and around 3k miles. In all the years of having key fobs I have never replaced a keyfob battery. (Last MX5 17 years old and still same battery).

I have googled how to do it and it seems fairly straight forward and states a CR2025 battery type which I will now get ordered.

Just wondering:-
a/ is it normal for the battery to run down so quickly? and

b/ is there anything else that needs to be done when the battery is replaced, ie to sync it with the car, or will it just carry on working as normal?..

Many thanks for any replies…

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They don’t seem to last long and in my experience you don’t need to do anything else.

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3

I’m getting the same with my 30AE which is 18 months old, and I’ve been getting the message for over a month. I haven’t changed the battery yet, but I do carry a recently bought spare, for when necessary. I did have to change the battery in my 2015 ND1 after about 3 years but (no screen message in that!) but it is simple and you don’t have to syncronise anything, just change and carry on as usual.

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4

Replaced batteries twice in ‘main’ key , once in ‘spare’ key in 18months. Can’t recall changing our NC one in 10 years

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5

I think the keyless entry uses the battery up a lot quicker. Also keep it far away from the parked car in a Faraday signal blocking pouch.

Mazda Gurus have a good little how to video here:

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6

Mine ran down quicker than expected, but easy to replace as has been mentioned.

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7

It’s odd that despite having had key fobs like the MX 5 one for many years - on VAG, Ford and Peugeot cars - I had never experienced a key fob failure until I got the Mazda. It was on my then 18 month old ND - but the only signal I got was not being able to get in the bloody car…

Talking of which, I can report that if you are stupid enough- and I am - to lock your key in a Faraday pouch into the boot early on a Sunday morning at an M1 services the locksmith will cost you 150 quid . :cry:

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8

Mine was flat at the dealers in September when I went to test drive it. They ran in and changed the battery in 2 minutes and I’ve bought a spare for storage in the centre box. Makes sense with keyless entry it’d be used up quicker.
Love the induction start up method if the battery runs flat though. Very neat way to get going again.

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9

The batteries in these newer Mazda fobs last about 18months, regardless of use or not. So the spare sleeping in its Faraday cage goes down within weeks of the one in daily use!

I just carry some spares, they are dirt cheap, small enough to lose (even in their card and impossible-to-open-without scissors blister pack), and typically have a shelf life in excess of ten years.
The user handbook shows how to change them.

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10

Yep. Agree with Richard here. I just took the battery out of the spare key fob and sellotaped it to the outside, so it is always there if I need it.

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11

Hi all and thanks for the replies…seems about normal then. Also like the idea of taking the spare out and keeping another spare in the car!..assuming you can get into the car if the battery is flat?!..although I assume from the onscreen IT you get a reasonable warning…

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Just an aside. :nerd_face: I keep a spare battery (in its card/bubble) in my wallet, then it’s always available, :+1: providing I don’t lose my wallet! :thinking: :-1: :crazy_face:

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13

Hi S,
Don’t worry you can still get in the car even if the battery is flat. There is a ‘blade key’ within the body of the fob.
:heart:

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14

As a warning that the key battery is getting low, the green key light on the dash will flash (5 times?) when you stop the engine.

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15

I get the low battery on both my keys on an 18 month old car. never ever replaced a fob battery in any other car for at least 3-4 years old.

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