Q..

I have just replaced the battery in my key fob.
No biggie. Done it several times before.

However this time, the "Replace battery key" message won't go away
Any suggestions ?

realjones88

Try the other key and see if you still get the message.

GRP

Had a similar issue.

Started vehicle, changed battery whilst in car and turned vehicle off and restarted and all was good (push button start).

AwdthisC63

Adjust the 4 tabs the battery sits on upwards. Be careful not to break tabs.

Q..

realjones88
I tried the other key. made no difference

That said, I managed to get it to clear.
I replaced the (new) cr2025 with a 2032 = FIXED !

Interestingly, I did it whilst in the car, which covers your process GRP
The thicker battery also covers your notion AwdthisC63, of increasing contact pressure.

Not entire sure which aspect cured it, but it worked.
Thanks guys !

GRP

Nice to know the 2032 fitted with no hassle - have thought of doing the same as my batteries were running down quickly - suspect keys kept to close to car when parked - now keep them in a 'lined" container to ensure no communication.

Q..

It did indeed !

I read that keeping them near coins is also an issue.

604 C63

Keeping it in the same pocket as your cel phone can be an issue.

Alex.currie44

I have been having a hassle since I got back from down south so after the 2nd change pulled out the old multimeter and the replacement was 3.1V spot on.
So I pulled up the tabs gently and the issue cleared.
This would explain why a CR2032 solved the issue. It is a thicker battery than the spec CR2025.
The CR2032 is a higher mAh capacity so may be the best replacement.
I chucked at my dealer a few years ago. They changed the key battery without asking so they were told to take it out. They charged $11.95 for the battery and 10 minute labour. I find the private label batteries pretty much the same in terms of service life as any brand name.

rjvelazquez

This worked for me and my 2011 C63 AMG, could not get rid of the "Replace battery message" on the dash, replaced batteries many times with out of the package with no good result, saw above fix, went right out to my C63 with the key fob started the car, got the error message, open the key fob and pulled the battery all the way out gave a 20 second count just in case, put battery back in and closed cover and cut off the car using the "PUSH START". Re-started the car with the "PUSH START" and error message flashed away all good now, this should have been in the manual.

CyanideRide

I've found that some of the lower grade "off brand" batteries will do this new from the package as well.

I usually try to stick with a brand name company 2032. It's the same voltage, might last abit longer so it's fine.

Yuille36

Disconnect the positive terminal lead from the vehicles battery for ten seconds and re-attach. Your issue should have now rectified itself.
It's the same as hitting CTRL - ALT- DELETE

trailsnail

same experience with my e550c today. inserted new 2025 batteries in both fobs and got the 'replace battery' message. used your solution and both fobs now work perfectly without causing the error message. thanks again!

cpsseals

Tried bending the tabs while in the GLK and no go. Replaced the new 2025 with a new 2032 and the message is gone after 2 years +. The 2032 is a tight fit, but it fits!

I'll post again if the message comes back within the next 6 months.

Thanks for the information!

Xzero

This worked for me as well, putting in a CR2032 has finally removed the REPLACE KEY BATTERY message on every start up.

How is it six months later? How often do you use the GLK?

Thanks!

jdra

I just cleared the Replace Battery message with a 2032

leewei

I have had this message to replace key battery for months, even after using new ones.

Turns out that for me, the problem is with the Duracell C2025 battery voltage.
I have one at 2.99V and another at 2.97V and both new batteries continues to cause the message.
These batteries are rated to expire 2023.

I saw on another forum that people have had success with Panasonic C2025.
True enough, with the Panasonic batteries, both my key fobs are now error free, and the batteries are 3.23V.

Zclassic

I'd like to second this. I bought a new 4 pack of Energizer 2025's as I thought the other "new" batteries, which were also Energizer's, were bad. After replacing the error message did not go away. I checked voltage of the new 4 pack and found 1 had .2v, 1 had 2.9v and 2 had 3.2. My fobs would not clear the message using a battery with 2.9v but did clear using a 3.2v battery.

zcct04

The improvement from using a 2032 battery makes sense, but . . . the 2025 isn't always easy to get out, and the 2032 is fatter. Has anyone using a 2032 tried removing it?

Cwagon

Its a little harder to remove but not impossible and worth it from a longevity point of view.
Btw I used Energiser, Panasonic and Maxcell at 2025 & 2032 and had issues with all not working and dying early.
Finally during my airbag recall last year I bought some Varta batteries from Dealer and they have been working great now for over a year in both my remotes.
Maybe like our car batteries Varta are the best.

Kameron562

This may have been recommended already but if you have push to start you have to manually put the key in and start the car that way, after that should it should resolve the replace battery message.

Cwagon

That was one of the first things I tried but didn't make a difference to "replace remote battery" sign on dash.
I'm sure like someone said previously, it has lot to do with the voltage of individual batteries.

advmedical

Actually, it’s all bull****, you simply have to replace the battery while in the car, and the “need new battery msg will leave. All the rest of the crap about bigger battery is wrong , use the correct battery and do the changing while in the car and turn car on and off and msg will go away.

DRBC43AMG

I've used Varta replacement batteries in all my fobs. Don't need to change them for years

Cwagon

I've done same since going through a few Maxcell and panasonic batteries that didn't last any time at all.