Hello everybody,
I like to share my weird problem with key fob hoping somebody can help. One of the key fob stopped working while other one works perfectly. Problem one cannot open doors but it is okay on ignition. I changed the battery, cleaned inside, no luck What it could be? I don't think it is fuse problem as other key works.

Thank you in advance

 

Does the red light fire up when you push buttons?

Ignition function is powered by car, rest by batteries in key.

 

No, I cannot see red light. I will check battery again. Maybe it is to sensitive and ask for quality battery ?

 

Swap the battery holders from working to non.

Quick, easy and costs nothing to do.

If it doesn't work with other batteries it may have suffered damage.

Frequently these keys suffer when the buttons crack and water gets in. Good news is there are ways to solve that.

But swap the battery holders and see what happens.

 

If there is no red light, it could be the batteries are inverted. Make sure the polarity is correct for both the batteries.

 

Thank you ManVidMB-V8 and shan, Thank you for your time. I appreciated that you answered.
I tried to swap the battery holder from non working one to working one. When I have uninstalled them found that they are not identical. They are totally different and there is no luck to try non-working one with this way. I checked the polarity of batteries but they are okay. I measured them and they give 3.06 v both. I cannot see any crack on buttons and I do not remember that any water got to the key. It just stopped working. Any idea?

 

Hi,

Yes, you have Gen 2 and Gen 3 Smartkeys.

Which one has no light/ no door function?

Are you in Europe? This look like Non-USA keys. (no "panic" button)

Can you take pic of other side of circuit board on problem key?

If you were in US I could fix it, but European keys use different frequency so you may need to find someone in EU to fix.

Sometimes there is electro migration from water combined with electricity that in effect electroplates some pins, shorting them. Will be a white/green powder. I have repaired one by just using a toothbrush and alcohol to clean the powder from the pins