2020 Fiesta Keyless Fob with engine start press button. 

I keep getting this warning message, despite having changed the battery in the fob. Various "reputable" brands have been tried and it happens with both fobs. The latest replacement appears to have lasted 14 days.

There are some on line responses that suggest varied button/clutch pedal etc presses but the manual does not show this requirement. Does anybody have any definitive answer, please?

 

4 minutes ago, FSTA1 said:

2020 Fiesta Keyless Fob with engine start press button. 

I keep getting this warning message, despite having changed the battery in the fob. Various "reputable" brands have been tried and it happens with both fobs. The latest replacement appears to have lasted 14 days.

There are some on line responses that suggest varied button/clutch pedal etc presses but the manual does not show this requirement. Does anybody have any definitive answer, please?

 

"Battery low....replace soon"

20 minutes ago, FSTA1 said:

"Battery low....replace soon"

There are lots of threads on this one, but if there's a definitive answer I don't think we've found it yet.

If the key is working after a battery change, I guess that rules out incorrect fitting.

Likewise, some batteries have a safety sticker which can leave a near invisible residue which needs to be cleaned off with meths or a similar solvent. Again, if the key works that would appear to be ruled out also.

That leaves the batteries. I found with my previous Fiesta the originals lasted 3 years, the Duracell replacements only 18 months or so. When I replaced the replacements, (Duracell again) one failed within 3 days. I replaced both as a precaution, using Energizers and all was ok up to parting with the car.

Still don't know if just bad luck or "fakes" which it seems are finding their way into even legitimate supply chains.

BTW (you may be doing this) but check replacement batteries before insertion - they should show 3.3v on your multimeter.

 

If like Roger has said, you are sure the battery voltage is 3.3V then you can do the keyfob battery reset procedure.

With the vehicle unlocked stand outside the drivers door. Use one of the keyfobs and press the Lock - Unlock, Lock - Unlock, Lock - Unlock. Three times in less than 10 seconds. This should then clear the low keyfob battery warning message.

I usually toss a response to these types of threads, but @Eric Bloodaxe and @unofix seem to have covered all bases already! LOL

1 minute ago, StephenFord said:

seem to have covered all bases already!

We didn't have a picture to go with the battery testing 🤣

57 minutes ago, unofix said:

If like Roger has said, you are sure the battery voltage is 3.3V then you can do the keyfob battery reset procedure.

Certainly well worth a try, but have to say, that it had no effect in my case. In all instances of low battery warning I had, I found the voltage of the key fob battery was below 3.0v. In the case of the one failing after 3 days, that one wouldn't open the car and I think the voltage was 2.8v when I removed and tested it. Fake or unlucky dud?

8 minutes ago, unofix said:

We didn't have a picture to go with the battery testing 🤣

LOL

2 minutes ago, Eric Bloodaxe said:

In the case of the one failing after 3 days, that one wouldn't open the car and I think the voltage was 2.8v

Only yesterday I had a brand new Energizer CR2025 (for a heater remote control) totally dead. Measured it with the meter and it was only 0.4V at first I thought I'd accidentally put the old battery back in. It just shows you can't assume that a new battery is good.

14 hours ago, unofix said:

It just shows you can't assume that a new battery is good.

Lol, conversely we "discovered" an old pack of AAA batteries the other day with an expiry of 2019. Popped one in a suitable device and it worked!

It seems you can't assume anything with batteries!

2 minutes ago, Eric Bloodaxe said:

It seems you can't assume anything with batteries!

Except they're not really suitable to power cars 🤣

Thanks so far, BUT--- I tried the reset procedure, but by the following day the warning message had returned. battery is showing 3.2v

On 11/26/2023 at 11:10 AM, FSTA1 said:

the warning message had returned. battery is showing 3.2v

Running out of ideas now, but was the battery showing 3.2v when you put it in, or have you removed it and re-tested after the message came up and found it on 3.2v?

This is what happened with one of mine. It was 3.3v when the (brand new) battery was inserted, failed next day (as in it wouldn't unlock the car), I thought it couldn't possibly be the battery but when I dismantled the fob yet again and tested, it was.