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Smart Key Battery Replacement

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26K views 54 replies 23 participants last post by  idrobbo  
#1 · (Edited)
So I got a warning about low battery today and bought a set of Duracell CR2032 batteries from Argos for £3.99. I have changed the battery, re-assembled and it doesn't work i.e. pushing lock or unlock buttons does nothing. I have also popped it in the slot and the car will start. I have had it in bits about 5 times now and can't see what the problem is. The + sign on the battery is away from the small circuit board.

Any tips or suggestions?
 
#2 ·
If the battery is correctly seated, I might suspect a duff one......

How long was the fob without a battery in it? I seem to recall they lose their programming if the battery is out for longer than a set time?
 
#3 ·
Think the Side touch on the battery can be iffy

Did it on mine when I changed battery ..... seem to remember having to bend it a bit.
 
#4 ·
You should be ok with new Duracell. I had issues with non branded batteries still showing as needing changing.

Can only suggest try your old battery again so you know your fitting it correctly and connections made. Then try the new / another battery.
 
#5 ·
If I hold the battery against the terminals it works, so I assume the side prongs are the problem. Commence bending...:asa:
 
#6 ·
Bending up or down seems to have no effect. Popping some folder paper behind battery to raise it also fails...:confused:
 
#9 ·
2032s, the prongs. I have tried bending the left on in the picture, up and down and the same for the two tiny arms on it to no avail.

 
#11 ·
Big red letters between main clocks appeared this morning for me.
 
#12 ·
Edit: ignore me I'm blind! :)
 
#15 · (Edited)
These are Duracells and they work if I pin them by hand, just not when fob is reassembled...



Popped the wife's fob open to play spot the difference, hers is in the rear. The side contact is at 90 degrees, mine is almost flat. One screwdriver twist later, two working fobs...:knuddel:
 
#18 ·
I just replaced the battery in one of my smart key fobs. All went well until while reassembling the side clips I noticed the end of a small spring sticking out of the side. With a sinking heart I realised that it must be the spring for the key release button which was nowhere to be seen. I spent the next ten minutes crawling all over the floor and the desk looking and feeling for it.
Eventually I went back and had a closer look at the fob and realised that the button is on the other end of the spring which just needed reseating properly before putting the whole thing together and putting the side clips back on. Whew, what a relief. Apart from that fiasco it's an easy enough job.
 
#19 ·
I know this is an old thread, but I came across it whilst looking for a solution to a 'Low Battery in Key Fob' warning issue I've been having.

When I bought my car at the end of Nov, it had this message on one of the keys, I changed the battery but had it again about a 10 days ago, changed the battery again, but two days ago I had it again. Now granted I'm using cheap batteries, but wondered if there might be another cause. Having read this thread, I bent the side contact so as to make a more positive contact with the battery and Hey Presto, the 'low battery' is working again and has been for two days or so since. This suggests a poor contact can also trigger a 'Low Battery in Key Fob' warning which might be worth trying if anybody has the same issue.

J500
 
#21 ·
Using quality batteries from a reputable source is the solution I've found. There are many fake proprietary brands around from ebay, Amazon etc.
 
#22 ·
I've just had my first 'Low battery in key fob' warning. Got home, grabbed the other key (which I've never used in 2 years) and tried it out. It ALSO had the same warning. This puzzled me - I would have thought that the spare key would have had more life in it, but I know that both batteries (Panasonic) were fitted to the fobs when new, so perhaps the current drain is the same, regardless of use.

Anyway - I set to work and pulled them both apart: defluffed and cleaned both, and gave a little nudge to the contacts. And remembered to keep the key release button aligned on reassembly.

Went out to the car with one key - no warning. Then took the working key fob back inside the house, and swapped it for the other one - it worked without warning as well.

This has me puzzled. However, I'll pop out and buy a couple of spare batteries just in case.
 
#23 ·
The last couple of days I've had a puzzling problem with my key fobs. The batteries were replaced about 3 months ago, and I tend to alternate the use of each one.

I've had no 'low battery warning' but using the fob to lock/unlock the car takes 2 or 3 attempts, pressing the buttons quite hard. This would usually indicate a low battery or connection problem with the tactile switches underneath, but a quick visual check doesn't reveal anything obvious. When it does decide to work, it still operates at a decent range. The keyless entry fails to work, but never had a problem once in the car with starting or when travelling. Any ideas anybody? :confused:
 
#26 ·
First thing I tried. However, this morning I went out to test them and they both worked fine, which leads me to suspect the receiver end. The battery wasn't particularly low but it did go on it's weekly trickle charge from the C-TEK overnight. Coincidence?
 
#25 ·
...and both of my keys now need new batteries. Odd how they both went at the same time. No matter - bought two new ones and all is good again.
 
#28 ·
Both my key fobs are behaving now. Batteries are genuine Varta and have been installed since October.
 
#30 ·
Do people really take them to dealers to change the battery? It's described in the manual how to do it!