The "Check Engine" light came on on my 2004 E320. Everything sounds and runs fine and the book says it is likely emissions so perhaps a sensor or something minor. (yes I checked the gas filler cap and yes I have plenty of fuel in the tank, LOL)
Dealer wants $125.00 to plug it in & my private shop charges $90.00 to run the same program.
Odd, when I called the MB dealer the rep said bring it when it is convenient, don't put it off but if it runs fine not something to get excited over.
I went through the dash options and it says there are no malfunctions.
Don't feel like ignoring it although in my Toy T-100 I would

Anyone have this come up and what was your problem when it was checked?

L

__________________
"Do not fight if there is nothing to be gained by winning."
Erwin Rommel

Are you seriously asking if someone has ever had a check engine light on their Mercedes, and think it will have any relation to whatever code your car is throwing? Its similar to feeling pain in your leg and asking to see other people's x-rays to find out what is wrong with yours.

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1985 500SL Euro w/ AMG bits 130k
1984 300SD Turbodiesel 192k
1980 240D Stick China 188k
2001 CLK55 AMG 101k
2007 S600 Biturbo 149k Overheated Project, IT'S ALIVE!!!

Take it to Advance Auto Parts or Auto Zone. They will run the OBD II for free.

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'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R

The malfunction display in the dash has zero zilch zip nada to do with the MIL OBD system.

There are hundreds and hundreds of codes (list here if you care to look: http://benzobsession.com/phpbb/viewtopic.php?f=31&t=3434 ) so the only way to know what's going on is to plug in a reader.

If you want to be a DIY-er, you need your own code reader. You can literally spend thousands on a fancy setup, but a basic reader that will read and erase codes is available at Amazon for under $30: http://www.amazon.com/Autel-MaxiScan-MS300-OBD-II-Scan/dp/B001LHVOVK/ref=sr_1_1?ie=UTF8&s=automotive&qid=1284752761&sr=8-1

But get this one read. Autozone, heck even Aamco says they'll run them for free. Be sure to get the codes, though, and not just their diagnosis or recommendation. Then come back and look up the codes on the list, if they don't make sense to you post them and we'll give you a hand.

Caveat: DO NOT IGNORE IT. It may be nothing, but it's also possible it is something minor that will in turn damage something that is really expensive, like a catalytic converter...CHA CHING$$$.

Good luck.

Wow, I can buy a reader for $30 and be able to check these things out without spending $90.00 just for my mechanic to for it???

That is great, thanks.

I am ordering that reader from Amazon right now and will save the codes from the link.
When it gets here if I have a question I will post.

So, to get started when I plug in this Autel MaxiScan MS300 CAN OBD-II Scan Tool and I assume there will be some instructions as to what I do it will show by code what is wrong??

This really is great.
I am often the one with advise on other forums and forget how much sharing helps us all. When I do it it seems like I am doing so little but when I get the advice I feel like I scored big!!

L

__________________
"Do not fight if there is nothing to be gained by winning."
Erwin Rommel

It plugs into the port under the dash sort of by your left knee, there's a little door that pops open and the port is behind it.

If you need to drive the car, since you can cruise by autozone or something I'd do that and get them read now for free. Otherwise don't drive the car until you get them read (i.e. don't drive around for a couple of weeks while that thing ships out of Amazon).

Either way a basic unit will just return the alphanumeric code(s) stored in the ECU. The codes you look up on a code list (like the one I linked above, I'm the one that posted it at Benz Obsession so I know it's accurate) and that may or may not lead you to a solution. For example if your code is P0130, then you know you have an O2 sensor problem (as well as WHICH sensor), so after checking wiring and connectors, maybe you need to replace it. If it's P0455 (again, for example) you'll know it's an evap leak, but that doesn't tell you what to do, so you have some diagnosis before you can figure out what's causing the code. And there are hundreds more codes to deal with, some minor, some simple, others...well, not so much.

If you buy a more expensive reader (like into the $100 range) you get not only the alphanumeric code, but also the translation (as in the linked table). But typically that isn't really very helpful, since you still need to figure out what's wrong. So the extra money is just wasted.

Good luck...

So if I get Autozone to read it they will have a better one and can more accurately determine it or will they more likely just narrow it down?

Either way I will find this Amazon tool useful if only it helps me understand a little better how the system works. Ergo, won't be so ignorant if a speak with a service guy about the problem.

I copied and pasted all the codes to my E320 folder, thanks for posting that

L

__________________
"Do not fight if there is nothing to be gained by winning."
Erwin Rommel

I decided I would spend the money and take it to my MB private shop (since 1994.)
He used a dedicated laptop hooked to a big portable box which I am betting was not from Amazon.com LOL

Anyway, he starts noticing a few things and says:
"The battery was replaced"

I said yes, by the dealer and he said they never reset a bunch of stuff and most do not except for things like the windows and typical stuff people would miss but as an example the left front door module reads an open or shorted circuit. yet the items mentioned work fine just were not reset for the computer to monitor them.
It does know know if the wipers can operate (They operate fine)
A few other things like that which do not actually affect operation just the computer to monitor said operation.
He said this is common because of the extra time the techs just ignore them. If they stop working you don't really need the computer to tell you sort of stuff.
Not right but.

Anyway, the check engine light on thingy was (Not on the code list BTW):

P2075-002: Purge control system has a slight leak (Minor leak): Leak in hose connection or shutoff valve of activated charcoal canister (P0456) and
P2026-004 Y58/1 (Purge control valve) Open circuit/switchover valve permanently closed (P0444)
(I just love the notation "slight leak", the fact the computer knows the difference is very cool, IMO)

He said the other stuff the dealer ignored does not really matter but he will gladly take my money if I want it done.

I did want the Purge control taken care of and that will be done Tuesday.

I still ordered that scanner from Amazon and will see what it said when I plug it in and compare it to the print out (he also DLed all his data to my USB drive so i can save it to my E320 file)

L

__________________
"Do not fight if there is nothing to be gained by winning."
Erwin Rommel