FormerC32Owner

So I've had my E550 since May, '07 with Keyless Go. For the past couple of days, I've gotten the message "Change Key Battery" on the information screen, intermittently.

Is it unusual to have the battery go out so soon? I used my other keyfob, and all is well with that one.

starbrite

Not unusual because it depends on the freshness of the battereies when they were initially installed.

Additionally, when I got that msg I pulled the batteries and measured the voltage. They were both 2.9 volts. (labeled 3v) so that warning comes on far to early IMO. You may also have gotten 1 battery that drained early, so check before replacing.

FormerC32Owner

Thanks Star. I appreciate the info.

pmb600

I didn't know that the car would tell you when to change the battery. Is it a good idea to change the batteries on a regular basis--say 1 to 2 years? Or should you just leave them until they die?

amdeutsch

Starbrite listed a good suggestions. I'd follow it in regards to the thread topic and battery replacement.

Barry45RPM

You can get the batteries at Radio Shack... they're cheap enough. I have Keyless Go & use the window dropping feature alot in the summer. I change the batteries every 8 months or so, just because.

FormerC32Owner

Thanks for the cost-savings tip, Barry! It's amazing what the markup at the dealership is...

pmb600

Why what does the dealership want for one of these batteries?

Barry45RPM

The "key" takes 2 batteries.

pmb600

Ok, so my question stands. How much does one cost from the dealer?

starbrite

As dealer parts pricing varies, let your fingers do the walking and call YOUR dealer's parts dept.

I bought mine at Waldbaums (local supermarket) @ $4.29 for a Duracell 2 pack.
The universal, all brands, # for them is CR2025

pmb600

Jeeze, no need for everyone to be so touchy. I don't need them yet I was just curious since everyone said they were so much more at the dealer.

Barry45RPM

You can bet they aren't anywhere near the Supermarket price.

starbrite

Well, you did repeat the question 2 hrs apart, so it appeared that you were itching for an answer.

Edit:We're not touchy, just trying to be helpful.

mpx220

Mercedes Benz of Pleasanton charges $23.00 for 2 batteries. They are just watch batteries, #2025 I believe. Cost $5.95 at local WalMart.

pinebaron

I found the best price at Radio Shack; I think these were $4.99.

JDM_SXE-10

Just make sure that you don't wait until the last minute to change them because I did that one time and I ended up not being able to lock my doors when I was out one night.

starbrite

Yep, but that's $4.99 each !

Heejin

Does this message show only with "Keyless Go" option? I am curious since my wife's key had some problem recently but never got this message.

starbrite

Yes.

pinebaron

You are right; but any expense for my car is justified, now if I could only find 18" wheels I like, it would be great.

Barry45RPM

Watch Batteries? LOL Each battery is the size of 2 quarters stacked... and there are 2 batteries! Thats a hell of a watch.

mpx220

That's what they are! Go look for them and they will be in the watch battery area.

bigmel

those batteries are to big for watches. useless you are flavor flav....lol

those batteries are used on computer motherboard to same Bios data, such as time and date. If you computer clock time keeps going back going back in time your battery is jacked up.