I do not recall exactly, but I believe the code scanners you mentioned only
provide the standard OBDII power train trouble codes. not the manufacturer
specific codes for MB To get the whole enchilada you need to spend a lot
more bucks. I bought this interface to  a PC type computer a couple of years
ago and I have used it on a couple of american cars and my SL 320. I think
it was around $ 70 and It has saved me a bundle, especially on my SL320.
The software and updates are free. It paid for itself the first time I used
it on an elusive problem on a 2002 Explorer that developed the CEL disease
right after the warranty expired. On my SL320 it led my right to the
problem.
http://obddiagnostics.com/index.html
I also ran across a web site that has a lot of good info on scanners and
TC's
http://pages.prodigy.net/jforgione/MB_S500.html

Peter

I gave about eight different OBDII systems a try several years ago.  Hand
helds, laptop programs, etc.

They all did basic OBDII data pulls.  They have to, it's US Federal law, the
reason OBDII is there at all.

What they imply, in these product ads, is that it will pull the additional
info that makes it interesting and helpful beyond the OBDII basics (which
are already vague and amazingly inaccurate in reporting some problems), and
that the user can access and control the internal systems with their
product.  If I were driving a Ford or Chrysler, I could possibly see what my
A/C line pressure and air intake temperature would be, but whatever is
available for US cars is clearly not there for MB on these products.

As an example, I wanted to test my speedometer accuracy (*cough* speeding
ticket  *cough*), but I was unable to locate a speedometer shop that could
run both front and rear wheels simultaneously.  Why wouldn't it work?  The
speedometer display is a calculation of electronic data pulled from all
wheels (or so I was told), and the only verification was to access the MB
diagnostic port with a hand held tester and do a road test.  Apparently, the
tester would display rpm, vehicle speed, etc. and that would verify the
dashboard display speed.

I spent a week checking out products, naively assuming they'd report more
than just basic OBDII codes (like intake manifold temperature, RPMs at shift
points, etc.) but in fact, none of the eight models I bought, upgraded,
tested, downloaded, connected or configured would do anything more on an MB
than the $35 OBDII plug-in tools you can borrow for free at AutoZone or
Schuck's. Any OBDII reader will work on an MB, and any OBDII reader will
give the same OBDII codes.  If you were hoping for the added features and
detail for MB autos, you'd need to go to a professional hand held tester.

Your E55 has a CAN bus, for example, and while it's got internal MB
diagnostic systems that are nothing short of spellbinding to watch (sitting
in the car during a test, I saw the A/C controls cycle through every
possible function setting, blower speed and air vent output combination; the
audio system turned on, turned off, raised volume, lowered volume, changed
CD tracks, tested radio stations, even opened and closed the tape door), all
those functions are not OBDII systems, they're MB diagnostic systems.  Like
the fiber-optic system that requires an MB CD deck, or the MB integrated
telephone system that only works with fiber-optic MB proprietary phones,
it's accessed through the MB diagnostic port in the engine bay, not the
OBDII connector under the dashboard.

I ended up not even keeping the most basic OBDII tester I found; instead, I
borrow one for a quick data pull while in the parking lot at Schuck's, and
if I want something from the MB system, I can first ask my independent
mechanic to see if his Snap-On hand held will get it, but failing that, the
dealer will connect and report from the STAR Diagnostic laptop for around
$90.

Hope this helps.

Rugbyguy
04 SLK32