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Honda Jazz Forums => Honda Jazz Mk4 2020 - => Topic started by: Hicardo on September 12, 2022, 08:53:38 PM

Title: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Hicardo on September 12, 2022, 08:53:38 PM
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
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: 5thcivic on September 12, 2022, 09:09:18 PM
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.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Hicardo on September 12, 2022, 10:31:44 PM
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
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Kremmen on September 13, 2022, 05:01:01 AM
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.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: ColinS on September 13, 2022, 07:50:32 AM
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.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Bristol_Crosstar on September 13, 2022, 09:25:49 AM
I've got into the habit of locking/unlocking by touching the door handle which probably saves the fob battery a bit.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 13, 2022, 09:41:13 AM
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  ;D 
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: ColinS on September 13, 2022, 10:03:41 AM
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.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Jazzik on September 13, 2022, 10:13:43 AM
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.  :o
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: aphybrid on September 13, 2022, 10:24:17 AM
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.

Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 13, 2022, 10:57:20 AM
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.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: ColinB on September 13, 2022, 10:59:15 AM
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?
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Jazzik on September 13, 2022, 11:02:28 AM
I didn't know it could be turned off by holding both buttons down, press one button to receive again.

(https://www.cheesebuerger.de/images/smilie/boese/a045.gif)

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  :D) the key...
Not all dealers seem to be the same, once the money £€  is in...
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 13, 2022, 11:09:23 AM
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.   
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: ColinS on September 13, 2022, 11:36:41 AM
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.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Saycol on September 13, 2022, 12:11:15 PM
I have had the car from new, now at 14 months and key fob fine. However having experienced “sudden death” on my previous car that also had keyless entry (VW Golf), I always keep a spare battery in the car.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Kremmen on September 13, 2022, 12:40:30 PM
Good point about spare batteries, must check what they are .................. CR2032
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 13, 2022, 12:44:26 PM


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."

My apologies   I missed that bit   :-[   .  That is indeed strange.   But the disadvantages of leaving  both keys on,  (and the admittedly very slight risk of  wearing out the buttons )  might still happen to others.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: BROC on September 13, 2022, 01:25:11 PM
We had similar problems with our other car (Nissan Qashqai) & motorhome.   We were in a public car park when both Qashqai key fobs failed to work unless we were almost touching the car. Later when I got home, they both worked perfectly on our driveway at a range of 7-8 metres.

Some months later I couldn't disarm the alarm on our motorhome while it was parked on our driveway. The alarm had only been installed a couple of months earlier.  I spoke to the installers & they suspected radio interference. They said the radio band the key fobs operate in is getting very crowded.   I was about to try the motorhome alarm 'emergency disable' feature  when suddenly the key fob worked & the alarm disarmed.

I wondered afterwards if our car problem had been someone deliberately trying to prevent other people in the car park from locking their cars, to facilitate theft? In the case of the motorhome I wondered if it was interference from the drone that was buzzing overhead at my neighbours house, it was busy taking photos & recording video for the estate agent handling their house sale?

Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Hicardo on September 13, 2022, 04:21:17 PM
Hi Folks, and thanks for all the comments. 

So today - both keys still not 'connecting with' the car from 25 metres - at home - but operate close to vehicle just fine, I'm talking within 3 metres.  Took the car off to Tunbridge Wells on an errand, parked up at the multi-storey, and guess what, the key I took with me worked at a distance of about 25 metres.  Go figure??   Came home and we're back to short ranges again. 

Wonder if its got anything to do with interference from somewhere locally that's just started up - maybe? I live in a rural environment, but guess it could be BT works or something, not that i've noticed anything.  My other car's fobs, VW, work normally. 

I will buy / fit some new batteries next and see what happens. 

 ::)

Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Kremmen on September 13, 2022, 04:43:37 PM
I never use the buttons. I leave the fob in my pocket and pull the handle to auto unlock.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: nowster on September 13, 2022, 05:19:20 PM
There are repeated reports of key fobs not working near RAF bases.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 13, 2022, 05:23:21 PM
I think the vhf signal from the  buttons works on a different  frequency to the keyless locking signal.

Maybe a neighbour has just  just installed a bluetooth device, wireless router ,G5 etc that is interfering  with it.

I know the americans are having problems with G5 as the frequency they use  (different to uk) is too close to aircraft sytems.

I saw an amusing thing on TV the other night.  Some people are changing their wifi router name  so it reads as a rude message to anyone detecting  nearby  wifi networks.    Im tempted to change mine from a meaningless code to "Hi Fatty"  ;D
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: nowster on September 13, 2022, 05:27:10 PM
I saw an amusing thing on TV the other night.  Some people are changing their wifi router name  to so it reads as a rude message to anyone detecting  nearby  wifi networks.    Im tempted to change mine from a meaningless code to "Hi Fatty"  ;D

That's been going on for years!
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 13, 2022, 05:43:48 PM

That's been going on for years!
I'm still in the whoopy cushion and itching powder  era. 
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: aphybrid on September 14, 2022, 12:28:29 PM
Increase range - key in hand hold against head and press button - silly but it works - o go on give it a try.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: shufty on September 14, 2022, 12:39:42 PM
...I hardly ever 'blip'  ;D
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 14, 2022, 12:47:11 PM
Increase range - key in hand hold against head and press button - silly but it works - o go on give it a try.
VHF signals straight into your brain?   

OK I tried it.  The Unicorns made me do it.  Oh look a squirrel .....

I didnt really  try. I dont want to make things even worse.  I'll take your word for it.   ;D
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Jazzik on September 14, 2022, 12:51:55 PM
Increase range - key in hand hold against head and press button - silly but it works - o go on give it a try.

IT WORKS!!!
(https://www.cheesebuerger.de/images/midi/konfus/c018.gif)
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: stiggysawdust on September 14, 2022, 04:01:17 PM
Silly as it seems but holding key on side of forehead really does work. Have known this a long time and people I tell never believe it until I show them.
On my previous HRV it  shows a warning on the dash when the key in use needs a battery change. Don't know if the Jazz does this as we haven't needed a battery replacement yet on our November 2020 Jazz. I rarely use the buttons, I just walk up to the car and open doors using the handle or on the boot, the button.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: shufty on September 14, 2022, 04:05:38 PM
...The MK2 keys may not have as much to do as the MK4 ones but I only changed the batteries in both keys once in 11 years.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Kremmen on September 14, 2022, 04:14:22 PM
I suppose older central locking keys are dead, except for the brief millisecond they transmit on button press.
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Lord Voltermore on September 14, 2022, 05:15:12 PM
Increase range - key in hand hold against head and press button - silly but it works - o go on give it a try.
I wonder if it will work by holding it against your belly. That would give me almost unlimited range.  ;D
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: nowster on September 14, 2022, 11:25:04 PM
Unlocking a car with your Brain - Sixty Symbols
Title: Re: Crosstar keys suddenly BOTH have a very short 'blip' range
Post by: Hicardo on September 17, 2022, 10:33:51 AM
I can see you've had a lot of fun with this thread...haha  :P

Back to original topic, just for a second. 

I have not changed the batteries in the keys, but everything now seems to have returned to normal without doing anything.  So I guess it must have been some kind of temporary interference.  Hopefully the problem has gone away  ::) ;D