Hi Tracy, I'm very surprised that on a 2021 car you needed to replace the keyfob battery. If after replacing it with a brand new CR2032 the keyfob is not working I would think either the battery is not in correctly, or that the replacment battery is faulty.

Since the car is so new then there should be no charge to sort out a none working keyfob.

Luckily, my company makes a product with an inbuilt PC board from which I have to remove the BIOS battery. I've got plenty of 2032 cells and can change one in a Ford keyfob in less than a minute.

Changed my key fob battery twice now because I read that batteries can be duds,  Still the same annoying message every time I start the car.  Have just spotted the "open  and close the car manually with your car key three times"  trick - and it works !!

Isn't the web great.

My "spare" key battery threw up the warning on the way home from 1st MOT, so 3 years. My other key did likewise a couple of days later, so I replaced both with new Duracells.

Yesterday got the warning again so replaced that, again with a new Duracell. No doubt the other key will do likewise next time I try it.

Interesting though that the replacement only lasted 18 months against 3 years for the original. Surely it can't be a case of Ford using a superior battery?😀

 

Hi Roger, this repeated 'low battery' warning often happens even when you have replaced the battery with a good quality battery and with 3.30V

If you stand outside the car and use the lock / unlock buttons on the fob and do the lock/unlock cycle 3 times in less than 10 seconds it will normally clear the low battery warning.

1 hour ago, unofix said:

If you stand outside the car and use the lock / unlock buttons on the fob and do the lock/unlock cycle 3 times in less than 10 seconds it will normally clear the low battery warning.

Thanks for the tip! It's mentioned a few posts back:

On 8/6/2022 at 3:33 PM, Flick said:

"open  and close the car manually with your car key three times"  trick - and it works !!

but I assumed, wrongly it seems, that "manually"  meant using the key blade and I have keyless ignition so don't have a bladed key. I'll give it a try when my other fob gives the message!

52 minutes ago, Eric Bloodaxe said:

I have keyless ignition so don't have a bladed key

I thought all keyless Ford key fobs had a 'hidden' emergency key blade accessed by pressing the two buttons at the pointy end, and in addition were also 'sleepy keys' to mitigate relay theft.

https://www.autoexpress.co.uk/ford/106556/ford-launches-new-keyless-fob-to-combat-relay-attacks

1 hour ago, Eric Bloodaxe said:

so don't have a bladed key. I'll give it a try when my other fob gives the message!

Actually you do have an emergency metal key blade, it's stored inside of the keyfob if you have the standard fob used by most Ford's in the last 6 years.🙂

https://www.fordservicecontent.com/Ford_Content/vdirsnet/OwnerManual/Home/Content?variantid=4477&languageCode=EN&countryCode=USA&Uid=G2009149&ProcUid=G1957435&userMarket=GBR&div=f&vCode=&vFilteringEnabled=False&buildtype=web

38 minutes ago, unofix said:

Actually you do have an emergency metal key blade, 

Yes the battery replacement instructions tell you to remove it first before splitting the fob. Don't want to faff about putting that in the lock (I'm sure to lose the cover for the key hole!) unless it's an emergency, though.

After replacing the battery, everything was fine. Locked the car last night, as normal. Came to unlock it - nothing. Used my spare to unlock the car, then sat in it with the other key in my hand and got the "no key detected message". 

Placing the key in the passive key back up position does allow the car to be started, etc.

 

Any thoughts, anyone, other than a dud battery?

Either you got unlucky and the key broke itself overnight, or more likely the new battery either magically discharged itself overnight or isn't quite fitted correctly. Take it apart and clean the battery and refit it, or try another battery - I would suggest swapping battery with the working key, but that's probably tempting fate as you only have one working key at the moment.

18 minutes ago, agraham said:

Either you got unlucky and the key broke itself overnight, or more likely the new battery either magically discharged itself overnight or isn't quite fitted correctly. 

Thanks, Andrew. I was dismantling the fob while you were replying.

Certainly installed correctly,but when I put the multimeter on it, the brand new Duracell that was reading 3.3v on Saturday, was down to 1.7v.

So replaced it with another new one from a different pack (reading 3.3v before installation) and all good so far.

Weird. So it must have been a dud and this not the first time I've had this with Duracells (unless Tesco are selling cheap counterfeits!).

3 minutes ago, Eric Bloodaxe said:

brand new Duracell that was reading 3.3v on Saturday, was down to 1.7v.

☹️

9 minutes ago, agraham said:

☹️

Indeed. So much for the quality promised by the pink bunny in their ads!

As Elmer Fudd often said ""wascawwy wabbit".

55 minutes ago, Eric Bloodaxe said:

Weird. So it must have been a dud and this not the first time I've had this with Duracells (unless Tesco are selling cheap counterfeits!).

I've often wondered if Poundland 'Duracell' are genuine.  Would have trusted Tesco a bit more. 

Might be worth sending the dud battery & packaging to be fake tested...

1 minute ago, TomsFocus said:

I've often wondered if Poundland 'Duracell' are genuine.  Would have trusted Tesco a bit more. 

Might be worth sending the dud battery & packaging to be fake tested...

That's a very good point, Tom. I wish I'd thought of it before chucking the packaging in the recycling which has literally just been collected by the bin men, and the dud battery in my "batteries for recycling bag", which is full of them so I don't know which one it is!

42 minutes ago, Eric Bloodaxe said:

and the dud battery in my "batteries for recycling bag", which is full of them

You can very often tell the fake batteries by the weight. If you've got a good set of drug dealer scales (no need to admit anything) you will find the counterfeit will be 20 to 30% lighter than the genuine cell

Well, everything crossed but the battery I replaced the apparent "dud" with on Monday, is still working so hopefully this Duracell is living up to the pink bunny's promises.

I've got some Energisers as spares this time, and have re-read the emergency key back up procedure as a precaution!

On 11/13/2022 at 3:27 PM, agraham said:

I thought all keyless Ford key fobs.....were also 'sleepy keys' to mitigate relay theft.

Only on newer cars - i.e. after some time in 2019.

9 hours ago, alanfp said:

Only on newer cars - i.e. after some time in 2019.

That was explained in the link I posted.

My wife's Fiesta keeps giving her the "Key Battery Low" message.  After I replace the battery, the warning usually comes back after a few weeks.
I always use Panasonic or Duracell batteries, not cheapos, so I have no idea what the problem is.

Hi

 

I've got the ford fiesta 19 plate and a notification came up to say my battery in my key fob was low and to replace the battery which I did. Then a couple of days ago I struggled to get into my car using the key fob so I changed the battery but just wondered why I didn't get a message come up in my car? (My car is not a push button to start or keyless entry)