keyfob battery failing with *no* warning

[dave_knight]

Unlocked my 18 plate Karoq SEL via the remote control this morning and drove for 15 minutes to my destination, parked up and jumped out, then tried to lock the car on the keyfob … *nothing* happened … no little red led on the keyfob flashing, no clicking of locks and folding mirrors, nothing.  KESSY also not working so could not actually lock the car …. created a bit of a heart stopping moment for a while there!  Fortunately I was able to start the car by pushing the keyfob against the start/stop button so got home fine and once the battery was changed for a new one (CR2032 fitted with some encouragement) everything worked like it should so no trip needed to the dealer for a warranty claim on the keyfob which was good!

 

Has anybody else experience the battery in their keyfob just failing with no warning, no messages/symbols on the dashboard and being stuck not being able to lock/unlock their car?

[JKW]

Don't forget, you CAN lock / unlock the car with the actual key ( located inside the key fob) by removing the cover (edge of drivers door handle) exposing the physical lock. With regards the fob battery failing I've no experience of this, but your tale has certainly prompted me to keep a spare CR2032 cell type battery to hand, just in case !

[OldKaroq]

On 27/10/2019 at 12:08, dave_knight said:

Unlocked my 18 plate Karoq SEL via the remote control this morning and drove for 15 minutes to my destination, parked up and jumped out, then tried to lock the car on the keyfob … *nothing* happened … no little red led on the keyfob flashing, no clicking of locks and folding mirrors, nothing.  KESSY also not working so could not actually lock the car …. created a bit of a heart stopping moment for a while there!  Fortunately I was able to start the car by pushing the keyfob against the start/stop button so got home fine and once the battery was changed for a new one (CR2032 fitted with some encouragement) everything worked like it should so no trip needed to the dealer for a warranty claim on the keyfob which was good!

 

Has anybody else experience the battery in their keyfob just failing with no warning, no messages/symbols on the dashboard and being stuck not being able to lock/unlock their car?

 

Thanks for this post.

I have not yet had a problem, but my car is a similar age.

I found this in the handbook

 

 The range of the remote control key is about 30 m. The battery must be re- placed if the central locking only reacts to the remote control at a distance of less than approximately 3 m away » page 282.

 

This could be used as a test of battery strength?

I did check to make sure I can get into the fob, and it revealed a CR2025 battery. I presume yours is the same but you managed to get it working with the 2032? (The 25 is 2.5mm thick, the 2032 is 3.2mm.)

[dave_knight]

Yes it could be as when the keyfob battery is running down it is not able to generate the same RF signal strength which means the range is reduced.  The challenge for me was that I am normally quite close to the car when I try and unlock it so would have generally have been within the 3m range most of the time I activating the keyfob so I did not notice any range reduction as a warning.

 

You are correct that the keyfob is designed to accept a CR2025 and that was what I found in mine when I remove the back.  However not having a CR2025 to hand and knowing what the CR2032 is electrically compatible with the CR2025 (so would not blow up the keyfob, it is the same voltage just a higher mAh capacity rating) I put one of these into my keyfob as I read in another VW forum that it would physically fit.  You are right that the 2032 is 0.7mm thicker than the 2025 so it fits into the space but does not 'latch' under the little notch in the keyfob which means that in order to secure the battery into keyfob you actually need to put the back on and the pressure fit of this keeps the battery in place!  This works because the -ve contact is in the middle under the cell and the +ve contacts are both at one end, so the battery actually makes electrical contact on only half of the cell and the 'notch' only serves to physically hold the battery in place before the back is put into place … in effect belt and braces.  The drawback of this means that if you drop the keyfob and the back pops off (you would probably have to drop it quite hard as the back is on pretty firm) then the CR2032 could go flying which may prove challenging to find!

 

Hope this makes sense?

[SurreyJohn]

There is probably a lesson here, if your car has two keys, occasionally swap the one in your pocket with with one sitting in a drawer at home.

 

Did you ever sit on the key in a pocket and accidentally keep a button pressed down thus flattening battery much quicker

 

[skoda1982]

Had to change mine just swapped the battery out of the spare key . I had a warning on maxidot  (CHANGE BATTERY IN KEY FOB )  every time i got in. Opened mine by flipping the key out then using the other key twisted in the reassess flipped the cover off hardest part was getting the battery out i used a pin. If your battery completely drains you can clip the cover off the door handle and use the key to open the door

r 

Edited 1 November, 2019 by skoda1982

[Hairball]

Even the spare key fob battery has a quiescent battery drain when not used. I would suggest replacing spare key fob batteries as well when you change the usual key fob battery. I had this with my Fabia, the main key battery was low and in no time my spare was as well.  I guess with KESSY some part of the key fob is always on so drains the battery.

[shyVRS245]

Wife's Karoq is just over 21 months old and came with standard KESSY. It also came with 2 keys. Yesterday she rang me to say she could not unlock the car by either pressing the key fob or touching the door handle. Unfortunately I had the spare with me 26 miles away from her. When I got home I walked upto the car and it opened with the spare when I touched the driver's door handle. Then I locked the car by touching the sensor on the door handle. Today even the spare key won't unlock the car so both key fobs have failed within 24 hours. Unbelieveable when the 3 keys on my Octavia Vrs245 still work after 26 months (no KESSY).

[Hairball]

As I discovered, when a battery warning for the key fob shows up, I change the batteries in all of the key fobs for the car as the RF transmitters and or receivers are active all the time.. The old days of button pressing to unlock and a key to start the car have passed.  

 

VW and others offer a solutions to a problem that does not exist, electric hand brake, A button instead if a key to star the car etc

[shyVRS245]

And to add to my joy today the outside light bulb (low energy 9Volt) failed. It had lasted almost 8 years and the new one purchased locally for £2.25 should last 10 years (according to the packaging).

[RichardPB]

The battery in my fob failed a couple of weeks ago without warning. Locked the car fine and when going to open it half an hour later, it wouldn't unlock. Red light on fob wasn't lighting.

 

Luckily I had a spare battery which got the fob working again. 

[shyVRS245]

Our Karoq now at the dealers turns out both battery key fobs were fine and AA Patrolman pinpointed an Anti-Theft Alarm Sensor issue.

[MJ1]

16 minutes ago, shyVRS245 said:

Our Karoq now at the dealers turns out both battery key fobs were fine and AA Patrolman pinpointed an Anti-Theft Alarm Sensor issue.

Hi I saw your other post, had you replaced the batteries?

 

Confused by the other post?

[shyVRS245]

19 minutes ago, MJ1 said:

Hi I saw your other post, had you replaced the batteries?

 

Confused by the other post?

No I decided to test the voltage of both batteries and they were as good as a brand new Panasonic C2025 battery which the AA Patrolman confirmed before discovering the real fault with the car (anti-theft alarm sensor).

[dave_knight]

Before I swapped the battery out in mine I did test the voltage and new CR2032 showed just over 3v, the old one I was swapping out read 2.7v which dropped even further then I load tested it with a 10Kohm resistor to simulate the 200uA that it is rated for in the datasets.  So a flat battery was definitely the cause of me.

[StEdmund]

On 01/11/2019 at 20:42, Hairball said:

Even the spare key fob battery has a quiescent battery drain when not used. I would suggest replacing spare key fob batteries as well when you change the usual key fob battery. I had this with my Fabia, the main key battery was low and in no time my spare was as well.  I guess with KESSY some part of the key fob is always on so drains the battery.

 

Hairball makes a good point and it is always worth bearing in mind that both batteries are likely to be losing power all the while; it would surely be a good idea to keep a couple of CR2025s handy. I wonder if the newer, much-mentioned motion-sensing key-fobs don't lose power when the motion sensor turns them off?

[agedbriar]

2 hours ago, StEdmund said:

it would surely be a good idea to keep a couple of CR2025s handy.

 

On my shopping list

[Hairball]

On 03/11/2019 at 16:29, StEdmund said:

 

Hairball makes a good point and it is always worth bearing in mind that both batteries are likely to be losing power all the while; it would surely be a good idea to keep a couple of CR2025s handy. I wonder if the newer, much-mentioned motion-sensing key-fobs don't lose power when the motion sensor turns them off?

 

I guess it's a trade off between stopping someone rigging up a mobile repeater and checking the motion of the key fob to stop the tea leaves stealing your pride and joy.

 

KESSY light required continual power from the key fob to transmit 'legality' to start the car via the car start button (as per my Fabia SEL), full KESSY enhanced that with unlocking the doors but probably didn't make a huge difference in quiescent power drain of the fob. The motion sensor probably using a giro and or an accelerometer in the new fob would still require continuous monitoring (and battery power) to switch on the RF signal. It's hard to say if this would be a lower quiescent drain to leaving a low power RF transmitter is difficult to state. One thing for sure is that all the supplied key fobs will sip battery power over time and given that StEdmund suggestion of carrying a spare battery or two makes a lot of sense.

 

Personally I never had a problem with the old key... unless the keyhole was frozen in the Winter that was a pain in the unmentionables. Oh and that the lock could be picked...

Edited 4 November, 2019 by Hairball

[StEdmund]

So - assuming that I've bought a couple of spare CR2025 batteries ..... where do I keep them??? I suppose I should keep one at home in the drawer with all the other odds and sods so that if the battery fails, I can get into the car and get going with minimal delay. But what if I'm away from base ..... should I keep a spare battery about my person???

 

I understand that a sufficiently healthy battery is needed for both entry into the car and to start it so, if I am away from base, I can prize off the keyhole cover (I must practise this) and get into the car ...... and if the keyfob doesn't have enough ooomph to start the engine ........... I can use the second spare battery which I'll keep in that little coin compartment.

 

This is progress? 😲

[Berisford]

54 minutes ago, StEdmund said:

...... and if the keyfob doesn't have enough ooomph to start the engine ........... I can use the second spare battery which I'll keep in that little coin compartment.

 

This is progress? 😲

The battery can be dead but as long as the fob (transponder chip thingy) is held in the specified place near the start button all will be well.....no battery needed.

[StEdmund]

9 hours ago, Berisford said:

The battery can be dead but as long as the fob (transponder chip thingy) is held in the specified place near the start button all will be well.....no battery needed.

 

Thanks for that information - useful to know. I conclude that if I'm away from base with a duff key-fob battery, all is not lost. 

[shyVRS245]

9 hours ago, Berisford said:

The battery can be dead but as long as the fob (transponder chip thingy) is held in the specified place near the start button all will be well.....no battery needed.

Try telling that to our dealership when they tried to start our Karoq last Saturday using the recommended chip start method and the car's maxidot gave a reading "KEY NOT DETECTED". It's still at the dealership awaiting a fix even though I gave them a list with 4 fault codes. Seems like we are yet another R & D guinea pig as our Karoq was one of the first in the UK so others may develop our key issue.

[agedbriar]

I too know of a recent case (with a VW Touran) where pressing the starter button with the key didn't work, only a new battery did.

 

Re-reading the instructions I tend to understand that the direct press is the fix of a possible system fault only (to be done with a working battery in the key).

A low key battery may invoke the same error message (that's why it's mentioned here), but it's a different matter (to be resolved with a new battery).

 

Edited 5 November, 2019 by agedbriar

[agedbriar]

I just tested.

 

On my 6 months old Karoq the KESSY function of the door handle starts working when the key is about 1.5 m away (the combined span of both my arms extended). It will be easy to periodically check the current maximum operating distance as the battery gradually discharges with time, so as to replace the batteries in comfort before they die.

 

The guy with the VW Touran DSG above had to run and buy new batteries while people outside the garage, in line for tyre change, were waiting for him to finally take his finished car out.

The doors were unlocked, but the transmission wouldn't come out of Park without a working key.

 

Edited 6 November, 2019 by agedbriar

[Zealboy]

On 02/11/2019 at 20:09, shyVRS245 said:

No I decided to test the voltage of both batteries and they were as good as a brand new Panasonic C2025 battery which the AA Patrolman confirmed before discovering the real fault with the car (anti-theft alarm sensor).