Simple Question



Pushing both buttons (lock, and unlock) will not harm anything. There will be no response from the car untill you push one button or the other. Dad and uncle are off the hook. A lose cable on the cars SLI (starting, lighting, and ignition) battery is probably the reason the car "failed to proceed." (It is only ordinary cars that break down.)
Now for some good news, and bad news. First the bad news. A loose battery cable can cause the voltage to stutter (for lack of a better word.) The sudden application and removal of battery voltage can cause large flyback pulses from inductive components in the electrical system. These pulses, though short in duration, can be hundreds of volts in amplitude. The car has a couple of computers that have all the high voltage protection of a rice paper door. They are the front and rear SAM. You may have one that is malfunctioning, hence the ESP warning, or it might just need to be properly "re-synced."
The good news is that Roadside can come and do it. If you just had a battery replaced at a Mercedes dealer they might do it under warranty. Call them and ask, can't hurt. If you ever need a SLI battery replaced, don't pay for labor at the dealer. Call Roadside, they will bring a proper battery, install it, and re-sync the computers, even out of warranty, and charge you only for the battery.
If the dealer is responsible for the loose cable, and a SAM is runined, they should pick up the tab, with free rental.
I hope you have a better day tommorrow.



