M104: can't obtain diagnostic readout
 

Hi all,

Wanted to obtain a diagnostic readout on my 95 E320 so searched the archives for the procedure. Per instructions, the ignition was turned to the ON position until the warning lights, etc were on. Then I pushed the button on the diagnostic connector for 2-3 seconds and released with no results. When the button was pushed the light energized as expected and went out when the button was released. I thought that if there were no faults stored that it would flash one time to indicate that.

Am I doing something wrong or is it possible that there is a malfunction in the testing circuit?

TIA

philmartin

You're doing nothing wrong.

Try holding the button down a little longer. This has happened to me, too, from time to time. I was either not holding the button down long enough, or I needed to turn off the ignition and turn it back on to get it to work.

Still no luck
 

sug,

Tried your suggestion at intervals of 5, 10 and 15 seconds. Between tries, I turned the ignition off and pulled out the key. I also tried again at 2-3 seconds. I also turned the ignition on and tried at 2-3 followed by 5 then 10 without turning ignition off between tries. No blinks ever appeared once the button was released. Any other suggestions?

philmartin

Geez, very strange. I have no suggestions.

You are doing nothing wrong.

You're not getting even one blink?

By the way, that led will show fault codes for anything related to smog issues. Your check engine light would have to be on, too, to have fault codes related to smog emissions.

FWIW, I was able to read a fault code of 8 blinks about a year back which I think is coolant temperature sensor. I didn't follow up at the time since everything seemed to be OK and the check engine light was NOT on when pulling the code. Was it supposed to be on? Perhaps the diagnostic system is/was malfunctioning.

philmartin

Phil,

After I cleared a few codes on my E320, it took about a week before it would give the one blink (all clear) code. I would just wait a few days and try it again. Did you unhook your battery recently? That will clear everything out as well and that too has caused mine to not blink at all for several days following that.

I bet it will work fine in about a week!

Dale

One more question Phil, have you made yourself a code reader yet? That little tool is invaluable and cost about 10 bucks to make.

Dale

95 E320
00 C230K

The code reader is a great tool.

Arther Dalton can e-mail you a simple diagram, and you can make one from parts purchased at Radio Shack.

With this tool, you can pull the codes from all of the numbered sockets for codes stored in all the other systems.

Most people don't know is that although '93-'95 W124's are still technically OBD-I, they are actually almost OBD-II compliant. Our cars actually store the same information as OBD-II, but the code numbers are not the same.

I have not made the code reader yet but would be interested in any info on that. Also, after the reader is made, the codes for the other systems. I am planning to keep this car indefinitely so that would be very useful information.

Please feel free to PM me with info or post here.

TIA

philmartin

here's the schematic on how to wire one and a picture of the one I built. I think it will all show up so here goes...

I guess I had better read a little more about how to attach images, sorry

I'll try:

I can't believe it worked.

What the picture doesn't show is that you need to mount the led and the push button on something. Arthur mounted mine on an empty 35mm film cannister.

ok, here it goes again.

now I'm excited, that didn't take much did it!!!!

I've been out with a back injury for the last few months so I've got a little time on my hands these days. If there is still a demand out there for the code readers I'm sure I could make a few up like the one I made in the picture. I think this one cost me about $15.

Anyone interested?

Dale

Dale,

I would be interested. PM me and perhaps we can work something out. Also, what are the other codes that can be read and how have you specifically used it?

philmartin

Phil,

I've used mine many times, it helped me solve a bad trans. over temp protection switch, EGR code, etc etc. I would highly recommend one. The one I made is a little more expensive than what one can be built for, I like things that are functional and look good too. :)

I haven't PM'ed anyone before on this site so if your still interested just e-mail me at jetforeman1@peoplepc.com and I'll make one up for you. I will sell it for what it cost me in parts and shipping to you, which just guessing would probably total about $20.00.

Also as a side note I would sign up for an ALLDATA account for your vehicle. It's $25.00 for the first vehicle and $15.00 per vehicle thereafter (annually). They have all the latest and greatest info on codes, troubleshooting, service bulletins and tons of other things. I'm a big believer in that site because it has helped me numerous times.

Dale

Waited a few days, tried again and ....
 

it works. Just tried it again this AM and got one blink after button release so guess everything is OK. Thanks for the replies and suggestions.

Now, if someone can explain why it was necessary to wait. Seems like something must have reset internally. The battery has not been disconnected recently nor can I think of anything unusual that could have caused this.

Phil

Good question Phil, I've asked this before and no one was able to give me the exact reason why. I just know that it can take up to a week before it starts to work again from experience.

I would assume that it has something to do with the internal memory looking for a number of starts to give it a reference point.

Sound good to you?

Dale

"No Codes Stored" flash will not activate until the ECU has done a test procedure of all Emissions systems and is satisfied of all relating to the Diagnostic Module
. This takes several drive cycles to complete.
[ some longer than others , depending on what is activated and needed for each test]
An added note -- A fault code has to go through a repeat process before it will trip CE, BUT, you can go back and see if the computer has picked the fault up before it gets to a stored code/CE lamp mode... This is nice when one does a repair and would like to know if fault is returning without waiting for the code to go through the time process of finally tripping CE
[ ie -- the fault has been recognized, but not enough times to CE indicate. but you can go see before-hand]

Here is a Manual from a Code Reader that happens to post Benz codes and procedures that one may find interesting info pertaining to some of these PIn locations/procedures and codes...
Will show other pin modules/codes for the Led tool...

http://www.autolib.diakom.ru:8000/CARS2/pribor/cs1000/manual/cs1000_mb.pdf

Arthur,

Great link. I assume that the homemade tool duplicates the one shown in the initial part of the manual. If so, then I have to try and understand how to use all this.

Phil

Phil
Good starting point is:
Go to page 31 and you will see where/how the tool connects to get to The HMF-SFI module [ pin #8] and the list of codes.

The procedure to get the codes is the same as your built-in led/sw......
More of that info in Archives..

Arthur (or anyone),

I tried to save that PDF file to my hard drive and am not having any luck. Have saved them before and don't know what is going wrong.

Phil

Hmmmmm, I had no trouble at all. I just clicked on the floppy disk "save as" symbolon the Adobe Acrobat tool bar, and it worked fine for me....:confused:

Paul,

I have 2 Adobe windows up: one for the reader which is labeled "Acrobat Reader" in the task bar and one for the file. Neither has a "save file" icon. In the file window header bar I went to "File". then "Save As" and it opens up a dialog box with choices of "File Type" which is HTML or Text. When I click text file it sets up a zero byte file on the desktop which is the location specified.

I have set up a shortcut on the desktop to the internet site so it can be accessed quickly but still can't save the PDF.

Also, how does one convert a current PDF file to a Word file so it can be edited?

Phil