Battery life for key fob...How long does yours last?

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North of Toronto
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2019 CX-9 Sig
Yikes, I only got 8 months or so on a cx9 fob. My garage is detached so 2 brick walls and anywhere from 30 to prob 80 ft distance. 4 months of that was covid, so car used maybe once a week on avg.

Oh well. Maybe I'll get luckier with the replacement battery. Could be the new car had a fob battery from months before my purchase date.
 
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2017 Mazda CX-5 GT, 2016 Mazda6 iGT, 2014 Mazda3 sGT hatchback
Keep your fobs in a metal box. See if that helps.
My fob is in a drawer 20 ft away from my CX5 in garage with 3 dry walls in between. I once brought a wrong fob (Mazda6's) and stepped on the brake. The CX5 dash said "your fob battery is low" ... It actually still can sense it that far away....
 
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16.5 CX-5 Tour/AWD
Agreed. Those batteries are thicker the the recommended ones...does it fit right?

There's a tiny gap because the battery is slightly thicker in the CR2032. The only issue I can think of is the weather sealing due to the fob housing not being fully closed. I have a CR2032 so I can attest to that but my fob is a 2016.5 so YMMV.
 
Why replace the CR2025 with CR2032? After all, the CX5 cost $30,000 plus and the CX2025 are $2.50 each at HD. Just replace them every 12 months for $5.00.
 
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2019 CX-5 Signature
Why replace the CR2025 with CR2032? After all, the CX5 cost $30,000 plus and the CX2025 are $2.50 each at HD. Just replace them every 12 months for $5.00.

Why? Because I have them on hand at the house. The plus is they will last longer. Why not?
 
My wife's fob just gave the warning this week (2019 sold 2/19). Seems like Oct 2020 must have been the expiration date on a batch of batteries at the factory.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Keep your fobs in a metal box. See if that helps.
My fob is in a drawer 20 ft away from my CX5 in garage with 3 dry walls in between. I once brought a wrong fob (Mazda6's) and stepped on the brake. The CX5 dash said "your fob battery is low" ... It actually still can sense it that far away....
There’s a way to put the unused spare key fob into sleep mode and prolong the battery life. Just not sure if it’d work for all Mazda key fobs including older and thicker ones.
Just wake up the key ;-)


Works on all Mazdas.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
My wife's fob just gave the warning this week (2019 sold 2/19). Seems like Oct 2020 must have been the expiration date on a batch of batteries at the factory.
Like you said, the Oct. 2020 seems to be the battery expiration month as my key fob is also givIng me the low battery warning after about 4+ years of service life. This’s the Panasonic CR 2025 battery which replaced the factory one on 2/28/2016.
 
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2020 CX5 Signature
I have a 2020 CX-5 Signature purchased about six weeks ago and the "press four times and hold" trick does not work on my key fobs. I've tried "press and release four times, then press and hold" and "press and release three times, then press and hold on the fourth time" and neither has the red light on the fob stay or the fob going to sleep.

What does happen is with the first press, I hear the clunk of the locks locking. Each subsequent press the car horn briefly sounds. When I hold the fob button down at the end of the sequence to theoretically initiate the sleep mode, the red light on the fob blinks quickly and continuously until I release the pressure.

Am I doing this wrong? Does the 2020 Signature fob not have this sleep function?
 
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2020 CX5 Signature
Update the next day: I checked the second key fob and it works fine.

Today I tried to use my key fob and while it would lock/unlock the car, I got the "no key fob recognized" error message on the dash and had to hold the fob up near the start button to get the car to start. After running my errands, I replaced the battery in the fob. Old battery = 2.997V, new battery 3.47 volts. Now the key fob won't lock/unlock the car, but will start the car if held up to the Start button.

Somehow I've screwed up my key fob. Any advice as to how to reset it back to normal would be most appreciated.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Update the next day: I checked the second key fob and it works fine.

Today I tried to use my key fob and while it would lock/unlock the car, I got the "no key fob recognized" error message on the dash and had to hold the fob up near the start button to get the car to start. After running my errands, I replaced the battery in the fob. Old battery = 2.997V, new battery 3.47 volts. Now the key fob won't lock/unlock the car, but will start the car if held up to the Start button.

Somehow I've screwed up my key fob. Any advice as to how to reset it back to normal would be most appreciated.
I’d not mess around the malfunctioned key fob and take it to Mazda dealer for warranty service. Remember to put original Panasonic CR2025 battery back in before you go.
 
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2020 CX5 Signature
I’d not mess around the malfunctioned key fob and take it to Mazda dealer for warranty service. Remember to put original Panasonic CR2025 battery back in before you go.
The original battery was a CR2036, but I will put the old battery back in before I go to the dealer.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
The original battery was a CR2036, but I will put the old battery back in before I go to the dealer.
What MY of your CX-5, and how many miles on it? Do you have newer style thin key fob showed in post #27 which comes with CR2032 battery?
 
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2020 CX5 Signature
What MY of your CX-5, and how many miles on it? Do you have newer style thin key fob showed in post #27 which comes with CR2032 battery?
As stated in a message a few posts back, the car is a 2020 CX-5 Signature. It has the same key fob as shown in the video; I would call it "rectangular" as opposed to the other "long, thin" style. The car has about 600 miles on it.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
As stated in a message a few posts back, the car is a 2020 CX-5 Signature. It has the same key fob as shown in the video; I would call it "rectangular" as opposed to the other "long, thin" style. The car has about 600 miles on it.
With the car so new, definitely you want the dealer to replace the problematic key fob if possible! Luckily the problem is consistent to see.
 
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2018 CX-5 Sport
This afternoon I went to start my car, and the start button blinked twice and it wouldn't start. I figured it was the battery so I went and got my spare battery, out of the 2nd fob. And that battery is stone dead! Then I tried to start my car again and this time it started, it seemed as if it took a while for my car and fob to pair. It started each time as I ran my errands. I checked the voltage of my working battery and it is 2.89 volts. It is a pita when the car won't start for no reason.
 
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Southwest Ohio
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'19 CX-5 diesel
... I figured it was the battery so I went and got my spare battery, out of the 2nd fob...

You can just put a dead fob against the start button to start the car.

Another thing I noticed with the key fob batteries in cold temperatures ... they don't like the cold. If my fob is laying out in the cold (let's say in the garage while I'm working on stuff) and it doesn't work, if I put it in my pocket for a while and warm it up, it'll work fine.
 
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2018 CX-5 Sport
What was odd with mine was it wouldn't even lock or unlock the doors at first, and after the car started it locked and unlocked the doors fine. I will buy a new battery tomorrow just in case it is the battery.
 
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