About 3 hours after a short trip to the supermarket - went to the garage to take the AMG on another short trip. All headlights and tail lights were on - vehicle not running. Could not turn off any lights. FOB did not turn on or off the car - no interior lights came on when I opened the door. Nothing - car totally locked up. I quickly changed the batteries in the 2 FOB's - didn't help. Tried to start the car with the FOB remotely - tried sticking it in the key slot - nothing. Depressed the brake - you can tell nothing is working - no travel in the brake pedal. The Vehicle batteries are both changed out 2 months ago. I have the trickle charger going - doesn't seem to charge. Door lights will still not turn on when I open the door. Vehicle is brain dead - think it must be something to do with the computer - anyone else had any sort of issue like this? Car has been fantastic until Friday evening.....Car has 67,000 miles - did all the service at Mercedes - never an issue other than tires wearing out quickly....

 

Your batteries are probably dead by now if your headlights have been on for the past 16 hours. Assume you would have run an OBDII scan if you had a scanner, but the problems you describe would likely have dumped hundreds of DTCs. Did you try pressing and holding the ignition start/stop button for 10+ seconds?

 

Sorry to read your chassis is acting unwell. This is your front SAM acting up. Your batteries are paying for this.


> Short term:
REBOOT the whole car! Power down then back up.
The sleepless SAM-CGW Gateway module really like reboots.


> Long-term:
Look inside the driver side fusebox for signs of moisture. Need new SAM?

Are Ignition Key functions: good or marginal?

Wondering if CAN-B is still functional or not: any bad/crazy module

 

Disconnecting both batteries might be necessary to invoke a reset. Check the battery terminal connection integrity. It's surprising how many service techs don't tighten the clamp bolts.

 

streborx: What's the deal with pushing the Keyless Go for >10 seconds? Never heard of that, tell me more, please

 

Few drivers are aware that pressing and holding for several seconds the ignition start/stop button will shut off the ignition system in the event such is ever necessary -- a stuck accelerator, for example. Thought trying this might be a way to remedy the problem before going to the trouble of disconnecting the batteries to reset everything. I miss when cars had keys that operated switches with real electrical contacts, and removing the ignition key really turned things off.

 

Beware ignition switch off means zero (electric) STEERING

I bet there's a safety such that F-SAM does not respond to S/S Button with vehicle rolling.

 

That's an interesting point -- maybe some of the owners who've experienced inexplicable shut-downs while driving can comment on their steering experiences. AFAIK, my G550 has electric assist steering, so the wheels can still be turned with the ignition off, but not without some added effort.