So i purchased a 2020 CX5 two months ago (Oct 3rd 2020) and a few days ago i tried starting the car and i received the error message "unable to detect key Fob battery low" i went out and i bought a three pack of duracell 2032 batteries and replace it. that didn't seem to fix the issue because i'm getting the same error message and unable to start the vehicle unless i hold the fob next to the start button. Before i take it to the dealer, can anyone give me some insight into what exactly is happening? thanks in advance.

 

Do you have the same issue with both remotes?

 

Yes both remotes.

 

Is the key , left in the centre console? That seems to cause issues. Try leaving it in your pocket. That works for me.

 

In the owner's manual for the 2016.5 CX-5, at least, it warns to avoid placing the fob in the storage areas. Uncertain exactly how far away (or buried away) the fob needs to be for the starting system to fail to sense it. But "in clear line of sight" seems to work fine. I've always carried in my pocket or placed it next to me in a little pocket area of the center console (near the shifter).

I'd also get into the habit of replacing the "coin" battery in the fobs annually. Haven't ever had a fob last two full years. So I keep ahead of the problem by just making it a "pre-winter prep" thing.

 

This looks like a Mazda stupidity at its height. I just sold my 16 year old Chrysler Sebring and the original fob batteries still worked.Why does Mazda fobs need new batteries every year?

 

Hmm, 16 year old battery in a device. ,auh ok?. Your the one? ha! I change everything in my house shop and garage that has batteries(not vehicles main battery however I do load test at least every seasonal change) annually. Its more a common sense thing and preventative maintenance. As far as MAZDA key fobs needing more frequent changing then other platforms....nonsense. That part I speak from records in the shop and personally experience helping customers. Most need their fob changed about three years at best. I think you can also check with AAA Insurance/Roadside on these facts.

 

The new Fobs, have to do a lot more, than the old ones, that only had to lock and unlock doors. I never replaced a Fob battery , in my 2002 Dodge caravan, after seventeen years of stop and go driving, and over 500,000km.

 

Fob battery life:- i am not sure as new cx5 Mazda owner. Many people claim the battery only lasts 2 years! It could be due to the fact that its emitting a radio wave constantly to the car to keep it engaged as the car is keyless driving. Ie. The fob could be in your handbag, and it would need to transmit a strong signal to the car to sync it whilst your driving or near car. That could explain why fob battery only lasts 2 years. My other cars, I'v only changed battery once in 15 years.

 

FWIW, about 4 years now with our CX-5 and we changed the battery of the key fob twice.