My 2003 E500 fails to start intermittently with the Keyless Go. All lights turn on, it will start with the key, but not with the Keysess Go button. Has anyone else had this problem? I took it to dealer, and they changed my key battery. It seemed to work for several weeks, and is now doing the same thing-not starting intermittently. Would really appreciate any suggestions before I take it back to the dealer.

 

The keyless-go receiver maybe going bad. See if the dealer could re-flash the firmware. If not, you may need to get a new one. It's located under the left trunk liner and sits on top of the NAV bracket.

 

Issues with intermittent Keyless Go functions are usually an indication of weak batteries so that may be something that you should try first. It's possible that the batteries need replacing again.

 

I had an issue w keyless go, when the red message light came on the instrument cluster that read "Key not recognized". It went away one i repositioned the key from the ashtray.

Last week, I received the message "Low Battery in Key". Went to the dealer and paid $18 for an overpriced battery.

 

Radio Shack. Less than 1/3 of what you paid, but no free coffee.

 

don't forget the donuts and bagels...

 

I had exactly that problem on two consecutive days when parked next to the same car at work; then I read in the manual that spurious radio signals emitted my sources other than the key may interfere with the key, this is not a malfunction. Next day I started parking my car in a different spot; never had a problem since. Low battery condition is usually displayed on the dash.

 

I've had the same problem - big pain in the ***. I had mb replace my battery for $20, nothing. I suspected the contacts after taking out the batteries and noticing how loosely they fit. Today I jammed a dime between the two batteries and crammed the key back together (wont quite fit with a penny).
Voila.
Problem solved!

 

Why not just bend the contact springs?