Chris. M

Hello guy's, i have a w209 2003.after i lock it for at least 10 to 15mins i can't open it anymore with my remote. Just i can open with the key and when i put ny remote in his place to start engine i'ts working normally. Anyone can help me plz??

MJ50

moved to W209 forum...
replaced keyfob battery?

Rudeney

Just FYI...the function of the key being recognized in the ignition switch vs. using the fob buttons to lock/unlock are two different circuits in the SmartKey. For the ignition switch, the key is inductively powered by a coil in the ignition switch module. i will work without a battery in the fob. For lock/unlock, it uses the battery(s) in the key fob. If the fob battery is weak, you can experience lock/unlock issues. Also, the antenna module in the car that receives the key's transmission can fail. First try new fob battery(s). If that does not work, switch the key from "global" unlocking by simultaneously pressing and holding the lock and unlock buttons until the fob's LED indicator light flashed 3 times.

Chris. M

No i didn't change fog battery but i will try to change. I already tried to reset my fog by pressing the unlock and lock keys and nothing is changed.

Chris. M

And a have another thing: after 8 hours i found my battery empy or have a half so my car never start. Any relation whis teh key or not? And what things will have problem and drain battery in w209? Thankk guyss♥️

Rudeney

There are a few things that can fail and drain the vehicle battery. One is the power/memory seat controller. The other is the fan for the temperature sensor in the overhead control panel. Of course there are other possibilities, but those are most common.