Hi all

we have a 2019 Kuga. On Monday was it and Tuesday cleaned the inside of the car. Had the stereo on the same time and on Tuesday whilst hoovering it out the stereo went off saying it was saving the battery. 
not used the car until today when the wife went out and it initially unlocked ok but then said key not detected, she pressed unlock and then it detected and started. She had a 15 minute driver all ok, walked the dogs and after an hour or so back to the car and it more or less did the same thing again. 
battery in the fob changed a few weeks ago and all ok. 
I tried the spare fob and it didn’t want to open the car, I opened it with the keyless option of holding the door handle and then it opened and closed ok and started the car. 
when I was cleaning the car I did have 1 time I was starting the car to move it and it came up key not detected but I got the key out the pocket and it started. 
I’m wondering if it’s the battery being a little low??

any ideas greatly appreciated 

Mike

Yes the car battery is low.

Charge the battery on the car using a Smart Charger.

Connect positive lead of charger direct to the battery terminal. Connect negative lead of charger to the chassis earth point - NOT to the battery terminal.

Charge for a full 12 hours (or more).

Thank you

Ok, so now my wife has taken the car out and had a good run, starts ok opens ok but it comes up with replace remote battery soon as low. We replaced it a month ago. Tried the second key and it says the same thing with that one as well??

The keyfobs only only work with high quality genuine CR2032 batteries.

Poundland and eBay Specials just don't do it. Replace with Duracell/Panasonic/Energizer from a reputable supplier.

Measure the new battery with a meter it should be at least 3.30V

One thing to note is that passive keys are live 24/7, so even the battery in the key you keep safe and never use, will expire at virtually the same time as the one used daily.  The only difference will be key fob presses for the boot etc.