ashmead

Two weeks ago I was driving home (only a four mile trip) when the red low battery charge warning came on. I parked on the street because it was snowing and my driveway is steep. A few days later I started it and quickly got the same warning, and then it shut off. Same thing with a few more tries. Voltage across the battery was 11.5 and apparently enough to operate the starter, However, when running, the voltage dropped to 10.5, so clearly a charging problem. After a bit, it required jumper cables to start.

I wanted to move the car off the street into my garage to check it out further, so I removed the battery and charged it. It's an MB battery and looks fairly recent, though I could not find any date markings. It charged back up to 12.7 volts and I reinstalled it. I didn't switch terminals or ground anything by mistake. Now I cannot turn the key in the ignition, and the steering wheel and shift lever are locked. Nor will the key remotely lock or unlock the car. The trunk can still be unlocked with the switch in the driver's door.

I suspect one or more fuses may have blown, or that the keyfob needs to be resynced. If I can get the car running, then I can address the original problem with the charging system. Any suggestions on what may be causing the car to be immobilized?

John Choi

try it again after 12 hours . these EIS cars are very sensitive to battery voltage fluctuations.

wallyp

No synchronizing on the key. The door locking operation has no relationship with the "ignition key" functions.

Just because it is quick, easy, and free, I would disconnect the battery for a short time, then reconnect it. If there is no improvement, it may be time to start checking the main fuses. There are several threads on this subject, with detailed info and photos.

Click on the "search" button at the top, then "advanced search". Scroll down to the "S-Class" and "W220" section. Enter a search term like "main fuses", and start reading and taking notes.

Dalplex

Buy a key test ring for less than 10 from bay and put in front of the EIS key hole. Inset your key or anything like into the key hole.

if you see it lights up for at least 5 seconds. No issue to fuse at least up to EIS, which caused key no turn issue.