I own a 2010 Mercedes Benz Luxury E350 with the Keyless Engine start feature, and today, while I was driving, the screen on my E350 just said replace car key battery, or something similar to that. I do not know how to access the battery in the key, or I'm not sure if it was a false alert. Please help me, thanks.

 

The Vehicle instrument cluster will not tell you the battery in your key will be replaced. also you should read your owners manual to get familiar with vehicle fault codes. TIP:do not try to open the key to remove the battery.

 

The battery in the key is easy (and safe) to remove - simply remove the valet key and insert it in the opposite side of the same end of the key, then give it a firm push. The cover will pop off the side of the key, exposing the battery.

 

The cluster does indeed notify you of battery changes (as you've experienced) - as previously indicated this is a simple procedure.

 

I just got the notice on my instrument cluster to replace my key battery on a one month old car. My dealer told me that the battery died because I am leaving it in the vehicle and that the key is talking to the car constantly causing it to die. He said I need to remove the key from the vehicle at night to prevent this problem. If this is true-what a crappy design; I have to remove the key every night from a locked garage and bring it inside? Can anyone else confirm to me that this is the case? Anyone leave the key in the car at night and not have battery problems? Thx.

 

Well, when you think about it this way, with the key left in the car, anyone can access the keyless features, inclusive of getting in your car and driving away. Your key doesn't know you, your key knows your car and vice versa. With the key in the car, any stranger can walk up and open the door, as the key is in close range proximity. This may be OK to do when your car is locked in your garage, but not good elsewhere.

 

I can't be the only one parking in a locked garage and leaving the key in the car-anyone else have this discharge problem? I ask because it's easier to leave the key in the car, as I do with my other vehicles...I just can't tell you where I live.

 

I used to leave the door from my garage to my house unlocked, and only locked the garage overhead door. Then neighbors started complaining their doors were opening "on their own." It seems there was a group of teens playing around with the equivalent of universal remotes, riding around having a good time randomly opening garage doors.

And what color is your E and where did you say you live again?

 

I would think it is more likely a faulty battery. The key is always sending a signal either in the car or out. How would we unlock or lock the car from outside.
Ask 220S. He always knows where to find definitive answers on this stuff.

 

The manufacturers of KG systems have designed it so that the "relay station attack" is within a reasonable distance (to prevent someone opening your car if you're in a store with the key in your pocket and the car's parked out front.) And within that distance the antennae transmits information back and forth. KG systems do use batteries faster than non-KG equipped cars. A year is about right for KG cars.

But even if you leave the key in the car, the transmitter is only triggered when you touch the door handle or push the start button. So theoretically it shouldn't be using any more battery power than if it was upstairs in your dresser drawer (where it probably really should be ) It's possible the IC low battery warning is confused (use the key FOB battery check instead) or the system is not working properly.

Also, the system does go into standby mode if the car hasn't been unlocked for a long time (which is why some people have complained about it not working properly after not using the car for a long time.)

I've had the IC show that the battery needs changing when it really didn't. I find that the key FOB battery check lamp is the only real way to test, and I think the IC gets confused sometimes. imho, the best way to deal with key FOB batteries is to just buy a few extra batteries (cheap at Radio Shack) and keep them in the car. You will never be stranded if the battery dies on you anyway. The valet key will open the car and if you put the key in the slot it will start since there's a transponder inside the key that doesn't need batteries. Then when you get the chance, go buy some batteries or just pop a one in if you've bought some ahead of time and kept them in the car.

Dealing with Porsche's Drive Block immobilizer system, I've learned to keep spare batteries in the car. Without a fresh battery the whole car shuts down

Speaking of garage openers, the method of thieves is to break the glass (in garage doors with those small rows of windows up top), and use a hook to grab the manual cord opener that hangs down from the motor rail. This was the MO for a series of robberies a while back in LA. The answer is to tie back that hanging cord so it can't be reached from outside.

 

Sorry, i know this is an old post, but I just wanted to share a similar issue with my remotes and the ordeal I had....

https://mbworld.org/forums/e-class-w...smart-key.html