W251 R350 - Unlocking unreliable. Locking fine. Drive around 2 mins, lock and unlock then work perfectly.

[Dogshome]

Hiya, the unlock on my R Class has gotten unreliable. The initial unlock when the car has been stood for 24 hours is the problem. Once it works, you can lock and unlock as much as you want.

It's cold (1C) and damp. Fob battery is 3V and barnd new.The little 12v auxilliary battery was replaced a few months ago as It had never been done since 2013. I've not had any other issues with the electronics. I do have an Icarsoft reader, and will have a proddle with that.


Any ideas? I'm thinking damp antenna or connector wherever the receiver is (I don't know)?

 

[RTs4me]

Just out of interest, what brand of fob battery are you using?

With my bike key fob, supermarket or corner-shop unbranded batteries don't work reliably, but Duracell/Panasonic/Varta are fine. I've no idea why!

 

[Dogshome]

New Duracell measuring 2.99V which is ideal.

I'll dig the other fob out though.

I came out this morning, slightly warmer, less damp than last night and no problem.

I'll try and find the receiver on ewa, then clean and spray. Unless someone has had this trouble and fixed it before?

 

[ALFAitalia]

New Duracell measuring 2.99V which is ideal.

Not really....A fresh 3V battery typically measures between 3.2V and 3.3V. A battery measuring below 2.7V is generally considered dead.....so its about 50% gone......but I don't think its the problem in this case.

 

[Dogshome]

3V open circuit is good as new. I'll get a new one anyhow as it could be 50% or less.

Duracell 2025

 

[ALFAitalia]

Hmmm.....OK.

3 Volt Battery: All You Need to Know

What Is 3V battery?3V battery refers to a type of battery that has a nominal voltage output of 3 volts. The term

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