Replace Key Battery?

[Lol6]

I have a two year old Sel diesel, 23,000 miles.

 

Went to start the car yesterday and an instruction appeared on the dash telling me to replace the key battery.  Only problem was that the same instruction appeared for all three keys so I am sure this must be incorrect.  One of the keys I have never used so it hardly seems like wear and tear.  There appear to be no other symptoms and the car seems to run fine, at the moment.

 

Has anyone had a similar problem and found the solution?

 

Thank you.

[Gizmo]

The batteries do only last a couple of years. 

[Lol6]

Thank you for the advice @Gizmobut would this apply to three batteries in three different keys, two of which have been little used or not used at all?

 

My wife has a VW Bora which is 16 years old.  We have owned it for 14 of those years and have never replaced either of the key batteries.  I know technology has moved on and is more complex but.....????

[adamjackdrew]

Does the car have the KESSY keyless system?  If so, are all three keys KESSY?  If so then, to my simpleton's mind, all three keys would have run the batteries out in roughly the same amount of time because they're always broadcasting - maybe, possibly?  I'm sure someone will correct me if I'm wrong.

 

If the car doesn't have KESSY, then I don't know...

[Lol6]

@adamjackdrew, it does not have Kessy.  I appreciate batteries wear with time but tell that to the Bora, or indeed my Mazda 6 which I owned for 10 years.  That did not need a key replacement either.

 

I will contact my dealer today but would really like them to offer a cogent explanation for this.  I will feed back anything I receive which is useful.

[Lol6]

Sorry, in my previous note I meant battery replacement, not key replacement.

 

However, the plot thickens.  The car handbook advises the tests for the key battery is the red light on the fob which should operate  if the battery is okay and it suggests if the fob does not operate beyond a distance of 3 metres the battery is worn.  These tests were passed with flying colour.  The light on the fob flashes as it should and I tested operation from a distance of at least 30 metres.  It was fine.

 

I wonder if this is a reminder which comes up every two years regardless of the battery condition.  I will make enquiries.  Further information to follow.

[MartiniB]

waited one month between got message and replaced battery

and only in that key which were in use.
https://www.drive2.com/l/514389748576420469/

 

second key doesn't ask for new battery,

but i tested it after first key got new battery and warning disappeared

[nicknorman]

I replaced the battery in my Kessy key after about 2 1/2 years. Other key (rarely used) is fine at coming up to 3 years. I have on occasion seen an instance of “low battery” warning but ignored it as it didn’t subsequently appear. I’d only be concerned about it if you got the warning repeatedly.

[Lol6]

Went to the dealer who fitted a new battery for £4.  I am guessing but I suspect the car is programmed to recommend the battery be replaced approximately every two years, regardless of whether it is worn out or not.  Now the battery has been replaced the other two have miraculously recovered and there is no indication that another new battery is needed.

 

Regardless, the problem is addressed and many thanks to those on the forum who offered advice.

[JackySi]

I think there is detection for battery voltage. I can tell you that from experience on Octavia we owned. It didn't have kessy and after few warnings "low key battery" or something like that, car didn't want to unlock any more. That was after 4 years of ownership. Kessy I'd say goes little faster. Key does not emit anything until car asks it to (touching key fob, getting into car (internal sensors) - That's my guess only!!! But it does continuously work inside car while driving (when you put key out of running car you get warning), so e.g. every X seconds it checks if key is present (two way communication).

Anyhow I would say that kessy has some sort of detection of battery level. I can confirm that due to ODB showing error "Key low voltage". The only way this could happen is that there is some sort of chip that checks that. Funny is however that no errors came on Dash yet, just on ODB.

[davembk]

I was also thinking this, that the other two are hardly used. But if they are the keyless entry type, then all 3 keys just sit 24 hours a day 7 days a week transmitting s radio signal, totally different to the signal that’s transmitted when the manual entry is pressed. So, although the main key draws on its battery more than the spares, due to manual locking etc, those spares still continue to drain their batteries. I’m going to remove them.