2021 CX-5 Key Battery Low

[msalvetti]

So today was interesting - I've had my 2021 GTR for four days, and today the car wouldn't start because the battery in the key was low. Held the key near the start button and that allowed the car to start. The battery was still strong enough to lock and unlock the car from a distance, which seems odd.

Thought I'd get this out there and see if anyone else had this happen. Hopefully just a bad battery. Will have to watch it.

 

[markjenn]

Symptoms don’t seem consistent with it being a bad battery, although it’s certainly the first thing to try. Do you have the fob on a key ring? I have had some very weird starting issues on various cars with key rings and other gizmos on the ring.

- Mark

 

[msalvetti]

Thanks Mark. That's a good point. I have a leather strap on the fob, but also a Tile. I considered the BT in the Tile might interfere, but it worked flawlessly until last night. Didn't try the second fob.

I replaced the battery and the fob went back to working normally. If it happens again I'll try removing the Tile and see if that fixes the issue.

 

[Ladd]

My 2020 CX-5 Signature was purchased six weeks ago and today I had to hold the fob near the Start button for it to be recognized. Locking, Unlocking and opening the tailgate via the fob worked just fine from a distance, so it didn't seem like the battery, but I'm going to replace it and see what happens.

 

[msalvetti]

Sounds like what happened to me. The 2021 had a message on the dash that actually said "low battery", and told me to hold the fob near the start button.

 

[minnesotaart]

One thing we've heard of on here: if you keep your fob in the house but still somewhat near the vehicle in the garage, it may be constantly communicating with the vehicle because it's in range and wear down the battery. Just a thought.

 

[goodedward19]

I have ordered today those Faraday pouches where I am going to keep the fob when not using the car, especially the spare one that stays most of the time close to the garage.

 

[Mazdiod2]

I popped open my spare fob and wrapped the battery with a piece of plastic wrap. Hope the battery will be ok if the the other one dies, but the batteries were made the same date so there's no guarantee.

 

[MyFirstMazda]

I popped open my spare fob and wrapped the battery with a piece of plastic wrap. Hope the battery will be ok if the the other one dies, but the batteries were made the same date so there's no guarantee.

If you have a multi-meter, check the voltage of the battery in the spare fob. I removed the battery not long after getting my car, and that battery was stone dead. It was never used. The battery supposed to have a 10 year shelf life according to the package of the new batteries.

 

[Mazdiod2]

If you have a multi-meter, check the voltage of the battery in the spare fob. I removed the battery not long after getting my car, and that battery was stone dead. It was never used. The battery supposed to have a 10 year shelf life according to the package of the new batteries.

Right. I just replaced both of them when the one ran down. I hope the spare will have some juice if I need it, but I will probably replace both of them again in a couple of years.

 

[ceric]

There is a way to shut down the spare fob completely. Search the forum. Very simple to deactivate and re-activate when needed.

My fobs typically last 2 yrs.
Keep you fob far away from your vehicles (some people leave their fobs in the garage. that is too close). Or, keep your fobs in a metal box. Tin foil works as well.

 

[yrwei52]

It’s nice to get a new Q85 battery (very expensive) as you’re supposed to. Another member failed to get a new battery even though the voltage of his battery had dropped to 3.414V over night.

 

[babscx5]

So today was interesting - I've had my 2021 GTR for four days, and today the car wouldn't start because the battery in the key was low. Held the key near the start button and that allowed the car to start. The battery was still strong enough to lock and unlock the car from a distance, which seems odd.

Thought I'd get this out there and see if anyone else had this happen. Hopefully just a bad battery. Will have to watch it.

I have exactly the same thing happening with my 2019 CX-5 except that I’ve now changed batteries twice, after I bought the car.

Message that battery weak, after which I changed the battery about 4 weeks ago
Using CR2025s
Attached a photo of the key fob.

Got a message again yesterday (after about 6 weeks) that my battery was low and that I should hold the fob close to the Start button.
The remote lock/open key fob stopped working.
I then held my key fob close to Start and that worked.

I used the spare key fob yesterday, and that worked!
That would appear to be a battery problem with my key fob, except that I'd changed the battery just 4 weeks ago!

Should I use CR2032s instead of CR2025s

The separate remote starter (black) works fine.

Thanks.

 

[Mazdiod2]

I bought some cheap new ones but found they had a short life so I got some better batteries with a fresh date code and I've had better luck.
Another thing I've done is somehow run the battery down some by inadvertently leaving the remote in a position where a button was left depressed for a long time.

 

[ceric]

I got a small faraday box to store all my fobs.
Tested it. With a fob is in it, and I held the box near the door, could not lock or unlock it.
$10 on Amazon.
Prevent fob battery drain and relay theft.

 

[HyFlyer]

... Should I use CR2032s instead of CR2025s ...

Idunno about the new fobs but for our 2016.5 and 2019 (older fobs) would get that message until I switched to the CR2032 battery. The little round cover inside won't snap back on but the fob itself will snap back together.

I suggest going to CR2032

 

[ceric]

The difference between 2032 and 2025 is the thickness.
20 (first 2 digits): diameter = 20mm = 2cm
32 (last 2 digits): 3.2 mm
25 (last 2 digits): 2.5 mm.
If you can fit in a 2032 w/o breaking it... it will last longer...
Same voltage = 3V.

 

[N7turbo]

I got a small faraday box to store all my fobs.
Tested it. With a fob is in it, and I held the box near the door, could not lock or unlock it.
$10 on Amazon.
Prevent fob battery drain and relay theft.

This will not prevent battery drain because the car is not trying to communicate with it. But it could prevent a relay theft.

If you want to save the battery, put it into battery save mode.

 

[N7turbo]

I have exactly the same thing happening with my 2019 CX-5 except that I’ve now changed batteries twice, after I bought the car.

Message that battery weak, after which I changed the battery about 4 weeks ago
Using CR2025s
Attached a photo of the key fob.

Got a message again yesterday (after about 6 weeks) that my battery was low and that I should hold the fob close to the Start button.
The remote lock/open key fob stopped working.
I then held my key fob close to Start and that worked.

I used the spare key fob yesterday, and that worked!
That would appear to be a battery problem with my key fob, except that I'd changed the battery just 4 weeks ago!

Should I use CR2032s instead of CR2025s

The separate remote starter (black) works fine.

Thanks.

What batteries are you using? I've been driving these cars for 10 years and I put the Energizer lithiums in. They last 2-3 years each.

My CX-5s:

2014: changed the battery once
2017: changed the battery once
2020: changed the battery once

And they were not dead, only showing signs of reduced range. No issues starting the car or any messages.

 

[ceric]

This will not prevent battery drain because the car is not trying to communicate with it. But it could prevent a relay theft.

If you want to save the battery, put it into battery save mode.

Save mode is great for the backup fobs.
I was talking about my frequently used fobs.
A bit extreme to put it into save mode everyday, IMHO.