When driving from the United States into Canada, our new E400 wagon (with American specifications) immediately recognized that it was in a country in which distances and speed limits were measured in kilometers rather than miles, and (though I did not use the menus to convert the speedometer and odometer from miles to kilometers while we were in Canada but chose to let them continue to register speed and distance in miles) the distronic system instantly adjusted to the speed limits in kilometers and regulated our speed accordingly--which was a boon for driving, since we had to travel more than 2000 miles before crossing the border back into the United States. But, when we returned to the United States last week, the car did not immediately--or ever afterward, so far--recognize that we were back in the United States. It did not change the time zone at the border (I did that manually through the menus), nor did it recognize that we were back in a country where speed limits and distances are measured in miles. In the left-hand display behind the steering wheel, in the lower left where the speed for cruise control is displayed with a little icon of a steering wheel, the speed is still given in kilometers, although the speedometer and odometer remain (as ever) in miles. The problem is that now the car, when I pass an American speed limit sign of 65, thinks the speed limit is 65 kilometers, rather than 65 miles, and slows me down accordingly. So I can't use distronic until the problem is corrected, unless I want to drive at 62% of the speed limit.

There doesn't seem to be any simple way to fix the problem using the menus in the car, and Mercedes advisors reached through the telephone assistance have so far been useless in offering advice on how to fix it. I have an appointment to take the car in to my local Mercedes dealer for service next week to see if they can solve the problem, but, in the meantime, because the service technicians at the dealer admit they have never encountered this problem, and because this forum has people who seem to know all the answers, I wonder if anyone has encountered and solved this problem or can offer any good advice.

While I'm at it, here's another curious problem. The sticker by my gasoline filler port tells me to use no gasoline under 91 octane but, as far as I can determine, no gasoline with octane higher than 90 is available for sale in my state. I had no trouble finding 91 octane gasoline in Canada, however, except once when I had to buy 94 instead. Has anyone else encountered and solved this problem?

 

I would tell the dealer to do a simple reboot of the system. If you wish you can do the same by disconnecting and reconnecting the positive terminal of the battery. Personally I never use the speed limiting function just turn it off! 2 main reasons: I usually drive 5 to ten over, second, the speed limit recognition system is definitely not perfect, its a nice aid that's it. Don't worry about the gas, 1 ROM is not going to be a problem at all. You can use 87 too without problems as long as you fill with a higher octane the next time you refill the tank. Manufacturers recommend the higher octane to ensure the engine works at peak efficiency, however all new engines will work satisfactorily with 87 though with a slight loss of HP. The computer automatically reduces engine timing to compensate.

 

you could also try a reboot yourself. hold the off button until the system comes back on
probably won't help, but easy to try...

 

You mention there is no easy way to fix the problem in the menus. Did you try the setting that switches between kilometers and miles?

 

Thanks for your suggestion. I'll try a reboot the next time I'm in my car, but we've started the system several times since we returned to the US, so I don't have high hopes that that will work.

 

When I checked the setting that allows you to switch from miles to kilometers or vice versa, which the man at the factory used to switch the car to kilometers before we drove the car around in Germany, I found, after returning to the United States, that it had been reset to miles, and I left it in miles during our visit to Canada. When we recently returned to the US from Canada and experienced the problem, I did check the same setting and verified that it was still set to register in miles, but apparently that setting affects the speedometer and odometer, which have registered in miles ever since the car arrived in North America and the setting was changed to miles by the MB USA Vehicle Preparation Center, but not the distronic speed limitation function, which must have its own way of figuring out whether it should register in miles or kilometers. Or there is a glitch in the software.

 

Thanks for your reassurance on 90 vs. 91 octane.

As for the speed limitation, I'll ask the dealer to do a reset. I understand why you don't use it, but I found it useful for not exceeding the speed limit inadvertently, given the power of the 6-cylinder engine, particularly since we were driving long distances on unfamiliar roads in another country. For long stretches at high speed with infrequent speed limit signs, one can, of course, set the speed limitation higher than the posted limit, although one must readjust it after passing another sign that resets it to the limit.

It is less urgent to have it working now that we are driving around home, but I do want to get it to work properly.