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!!!!