Crosstar keys suddenly BOTH have a very short 'blip' range

[Hicardo]

Trying to puzzle this one out. 

Yesterday, and ever since I bought the car in June 2021, both keys have blipped open and closed the car from a 25 + metre range. 

Today, for the first time, neither key will do this.  I now have to stand right next to the car in order to lock / unlock - no matter which key I use.   I can see one key battery getting low after a year maybe, but both at the same time, seems weird. 

Anyone else experienced this situation, or any thoughts? before I go try replacing batteries

[5thcivic]

Do you switch them off or are both on all the time? A year and a bit does seem low but possible I suppose if used most days several times, or were poor quality batteries from new.

[Hicardo]

they're on all the time, I didnt realise you could switch them off until today! brand new car, unlikely they were poor batteries.  Odd to malfunction on the same day tho...thats what I cant understand.  it would be more likely that there is a 'featurette' on the button presses, that id accidentally done

[Kremmen]

As I've understood it, these keyless fobs are constantly active so the batteries will probably need changing more frequently.

When I got mine I disabled the spare and I frequently disabled the active one after home parking.

After my first annual service I swapped keys and my now spare is disabled and the now active key should be OK for the year

Be interesting to know how frequently the battery should be changed though.

[ColinS]

I will be interested to see if a battery change fixes the issue.  I somehow doubt it as it is too much of a coincidence for both batteries to go dead on the same day.  Perhaps there is some kind of clever electronics going on that detects a low signal from one and switches it to short range.  Not sure why Honda would do that though.

[Bristol_Crosstar]

I've got into the habit of locking/unlocking by touching the door handle which probably saves the fob battery a bit.

[Lord Voltermore]

The keys are constantly putting out signals, , not just when you press a button  , and regardless of whether the car is within range to react to the signal.    Thats why the key battery typically only lasts a year.  So if both keys are left 'on' they may  consume  their batteries at about the same rate, and go flat at about the same time.

I take the following precautions   . Spare always off.  I keep the main key on, but in a faraday bag when not in use ,  but many folk prefer instead to switch  it off and on   each time .      I also keep a spare battery of the correct size in the car. (  If necessary I could get into the car using the slide out emergency key blade built into the key. )  The battery is much easier to change than  was usual a few years ago. 
 
Also as the key is now a year old I will probably fit a new  battery as a precaution. I havnt yet so thanks for the reminder   

[ColinS]

So if both keys are left 'on' they may  consume  their batteries at about the same rate, and go flat at about the same time.

But on the same day .  I don't believe in coincidences.

This is all very interesting information about the general operation of the key fobs but I am not conviced that it is the OPs issue.

[Jazzik]

Our Jazz had its first service last week. Asked if the key battery was also replaced. The answer was no plus a question: "Do you always switch off the key? If so, then the key will certainly work for another year".
The key of our previous car (Yaris Hybrid) has worked for more than 4 years without changing the battery...

And this case sounds like a miracle: 2 batteries decided to give up at the same moment. 

[aphybrid]

Page 169 in manual says about 2 years life depending on use of course, also says to avoid placing near electrical appliances such as TVs and personal PCs.

I didn't know it could be turned off by holding both buttons down, press one button to receive again.

[Lord Voltermore]

Life may be 2 years from when the key  battery was first inserted and tested by the key manufacturer.  This could be months before  the car is actually built and then transported by sea to europe     I had something similar happen once to the battery in a small dash cam. 

 I agree both keys at once seems too much of a coincidence,   But if you are first alerted by your main key  going flat and only then try to use the spare ,that might  already have been flat  for the last few weeks or months.

[ColinB]

The keys are constantly putting out signals, , not just when you press a button  ... 
... I keep the main key on, but in a faraday bag when not in use ,  ...

So the main key is constantly transmitting & listening within its bag ... how does that preserve the battery?

[Jazzik]

I didn't know it could be turned off by holding both buttons down, press one button to receive again.

On delivery of our Jazz, for which the dealer took plenty of time, we were also told and shown how to turn off (and on  ) the key...
Not all dealers seem to be the same, once the money £€  is in...

[Lord Voltermore]

The keys are constantly putting out signals, , not just when you press a button  ... 
... I keep the main key on, but in a faraday bag when not in use ,  ...

So the main key is constantly transmitting & listening within its bag ... how does that preserve the battery?

It doesnt.   But on my Yaris the battery lasted 14 years,it was the buttons that  started showing their age with repeated pressing. (same is starting to happen with the most used button on my tv remote)    Probably not a problem, but I already had a faraday bag, and would rather change the battery annually than risk dodgy button contacts.   

[ColinS]

But if you are first alerted by your main key  going flat and only then try to use the spare ,that might  already have been flat  for the last few weeks or months.

The OP says that both were fine the day before:

"Yesterday, and ever since I bought the car in June 2021, both keys have blipped open and closed the car from a 25 + metre range."

@Hicardo.  It would be good to get an update when you have one.